SequentialChoicesandPartisanTransitions
in U.S. SenateDelegations:1972-1988
GaryM. Segura
Stephen P. Nicholson
Universityof California,Davis
A recent increasein the numberof states sending mixed delegationsto the U.S. Senate, i.e., having
one senatorof each politicalparty,has led scholarsto ask why essentiallystableelectoratesproducedifferent partisanoutcomes. We contend that the existing argumentsdo not, and cannot, adequatelyexplainthis phenomenon.The failureof these earlierattemptsis the directresultof a misinterpretationof
the choices faced by voters in sequentialelections. The existence of mixed Senate delegationsis not all
that extraordinaryin an era of candidate-centered,ratherthan party-centered,campaigns.In short, sequential,binarydecisionsarenot equivalent,and mixed delegationsareperfectlyconsistentwith general
expectationsof voting behaviorand electoralpolitics.A model consistingof election-specificvariablesis
used to predict transitionsto and from mixed delegations,and to directlytest, and reject,the primary
existing explanation.
EachCongresssince 1972has had 21 or more Senatedelegationswith one member from each party, and in the Ninety-sixth Congressthe number peakedat 27.
We believe that this increasinglycommonphenomenondepictedin figure 1 is consistent withJacobson's(1990) observationof "a patternof electoraldisintegration"
(7). He and others (Alesina and Rosenthal 1991; Cox and Kernell 1991; Fiorina
1992) have accumulatedan impressivebody of evidence that the electorateis increasinglylikely to abandonpartisanloyalties, express inconsistent preferences,
and divide their votes.
The Senate problem, as it has been conceptualized,is distinct from the more
generalquestionof dividedgovernmentin two importantways. First, except in the
rarestof instances,delegationsare elected sequentially.When explainingdivided
government,we examinea single pool of votersmakingmultiple, and inconsistent,
decisions on the same day. This simultaneitycreates an informationdeficit that
can, at least in part,accountfor apparentlyinconsistentbehavior.The electionof a
An earlierversion of this articlewas deliveredat the 1992 annualmeeting of the AmericanPolitical
Science Association,The PalmerHouse Hilton, Chicago,Sept. 3-6, 1992. The authorswish to thank
the discussants,Dan Palazzoloand David Rohde, for their thoughtfulsuggestions.In addition,helpful
comments were offered by Bob Jackman,Ross Miller, Randy Siverson, and Scott Gartner,all of the
University of California,Davis. Gloria Cornette,of the Citizens'ResearchFoundationof the University of SouthernCalifornia,was helpful in providingearlycandidateexpendituredata.Researchassistance was providedby JenniferBrustromand her help was greatlyappreciated.
Vol. 57, No. 1, February1995, Pp. 86-100
? 1995by the Universityof Texas Press, P.O. Box 7819, Austin, TX 78713-7819
THE JOURNAL OF POLITICS,
7
SequentialChoicesand PartisanTransitions8
FIGURE 1
NUMBER OF MIXED DELEGATIONS: 1948-1988
28
26.
24
22
4f1
20
18
16
0l
Z
14
12
10
8
1945
-
1950
1955 1960 1965 1970
1975 1980 1985
1990
Year
Senate delegation,however,occurs in two iterations.Voters have informationregardingthe outcomeof the other raceincludingthe partypreferenceand behavior
of the other senator-information that they lack when multiple elections are held
simultaneously,where all resultsare uncertain.
Second, explanationsthat focus on the variancein the populardemandsassociatedwith particularinstitutionsarenot helpfulin explainingtransitions.Jacobson's
(1990) observationsregardinghow expectationsof the citizenry differ from the
House to the presidencycan account for behavioralvariancein voting decisions
acrossbranches.But sequentialdecisionspertainingto Senateelectionsare,on this
issue, essentiallythe same-institutional expectations,therefore,should not vary.
decisionsmadeby
The divided Senate delegation,then, results from inconsistent
An
betterinformedvotersunderidenticalinstitutionalcircumstances.' answer, then,
'One possibility is that demographicchanges in the electorate are driving transitions. If so, we
shouldobservemorefrequenttransitionsto mixeddelegationsafterfour-yearintervalsratherthantwo-
88
GaryM. Seguraand Stephen P. Nicholson
may provide importantinsights into the causes of divided government.We argue
that existing explanationsof this phenomenonbased on voter characteristicsare
unsoundand resultfrom incorrectassumptions.We offer an alternativemodel that
predicts transitionsto and from mixed delegationsthat is built strictly upon the
politicalcharacteristicsof each race. Our results lend strong supportto Jacobson's
(1990)explanationof electoraldisintegrationundermoreconstrainedcircumstances.
EXISTING APPROACHES
StrategicCitizen.The first approach,which we call the strategiccitizen model,
has been proposedby a numberof scholars(Alesina,Fiorina,and Rosenthal1991;
Fiorina 1992). The strategiccitizen model begins with the recognitionthat Senate
electionsare a serialprocess.There is a sitting senatorwho is not facingthe voters
at the time of the election.2A criticalnumberof citizens, it is argued,recognizethat
representationin the Senate is accomplishedthrough two delegates rather than
one. Ratherthanbeing concerned,then, aboutthe ideologicaltenor or partisanship
of each senator,voters "mayvery well care about the total representationof their
state in the Senate"(Fiorina 1992, 83) and seek a delegationthat, as a whole, approachesa moderateideologicalideal point.
As in figure2, if the sitting senatorlies to one side of the ideal point, the strategic citizen will vote for the currentcandidatewho is closest to being as far fromthe
mid-point as the sitting senator, but on the opposite side. Alesina, Fiorina, and
Rosenthal(1991, 9) call this tendency the "oppositepartyadvantage,"since, in all
but the rarestinstances,that candidatebest able to "balance"the sitting senatoris
from the opposingparty.The idea is that the resultingdelegation'sideologicalmix
will approximatethat of the strategiccitizen.
This model is built upon three assumptions:(1) the median voter's ideal point
lies between the sitting senator'sand the candidate'sof the opposite party;(2) the
candidatefromthe oppositepartyis fartherfromthe sitting senatorthan the candidate from the senator'sown party;and (3) the state ideologicaldistributionis more
or less normal.If any of these three assumptionsareviolated,the findingof an "opposite party advantage"is likely wrong. In fact, this erroramounts to little more
than a failureto conceptuallydistinguishthe nationalpartisandichotomyfrom the
ideologicalcontinuumwithin a state.
Empirical support for this "advantage"is weak at best (Alesina, Fiorina,
and Rosenthal 1991), having a significanteffect only for incumbentsand only in
allowingfor more change-and subsequent"corrections"to unifieddelegationsaftertwo years,reflecting enduringpopulationchanges.Of the 165 validtransitionsbetween 1948and 1988,91 tookplacetwo
yearsor less since the electoratelast exhibiteda senatorialpreferencefor the oppositeparty,while only
74 took place after the longer intervalof four years.That transitionsare more likely to occurafteronly
two years(or less) suggeststhat demographicchangesand their politicalimplicationsarenot drivingthe
creationof mixed delegations.
2Fromthis point, the term sittingsenatorwill alwaysreferto the memberof the Senate notrunningifl
the currentelection. For membersparticipatingin the election in question,the term will be incumbent.
SequentialChoicesand PartisanTransitions
89
FIGURE 2
STRATEGIC CITIZEN MODEL'S DISTRIBUTIONAL ASSUMPTIONS
DC
M
RC
RS
DC-Democratic CandidateIdeologicalPlacement
RC-Republican CandidateIdeologicalPlacement
M-Population Mean IdeologicalIdealPoint
RS-Republican Sitting SenatorIdeologicalPlacement
presidentialelectionyears.3But more importantly,to the extent that this "opposite
partyadvantage"exists, it is more a descriptionof an aggregate-levelempiricalregularitythan an ex ante factorthat contributesto the individualvotes which are collectivelyproducingthese outcomes.While Fiorina(1992) laterstipulatesto the "as
if" characterof this model, such a stipulationis insufficientwhen drawinginferences about individual behavior based on collective, occasional,regularities.In
short, the dataand analysisemployedin existing researchdoes not providea plausible nexus between the political dynamicsdescribedand the individualbehavior
necessaryto producethese outcomes.
The most seriousobjectionofferedto the strategiccitizen model is the portraitit
paints of the Americanvoter. The strategicbehaviordescribedrequires:(1) that a
crucialsegmentof the electoratepossessesa largeamountof informationconcerning the ideologicaltendenciesof the sitting senator,both candidates(includingany
incumbent), and their own preferences;(2) that citizens can accuratelyevaluate
this informationand calculatewhich of the availablechoices would produce the
ideologicaloutcome most desired; and (3) that citizens act on these evaluations
by voting for a candidatefurtherfrom their own position in hopes of achievinga
3This finding is not surprisingand might well be an artifactof the politicaltrends in the executive
branch.In 1965, Democratsheld 26 unified delegationsand sharedin 16 mixed delegations,while in
1985 they held only 12 unifieddelegationsand sharedin 23 mixed delegations.Over the same interval,
Republicanswon 4 of the 5 interveningpresidentialelections.We fully expect, then, that in presidential
election yearswhen incumbentsare running,a disproportionatenumberof losers (or less than impressive winners)were Democratsrunningin stateswherea Democratheld the other seat.
90
GaryM. Seguraand Stephen P. Nicholson
long-run strategicoutcome. This model predicts a significantnumber of citizens
voting for both the sitting senatorand his or her ideologicalopposite.
We arguetwo points in responseto this portraitof the strategicvoter. First, the
model actually underestimates
the demands made on the citizenry because it assumes that citizens are interestedin the ideologicalcast of their Senate delegations
but not in public policy outcomes.It is more reasonableto believe that policy is the
centralconcern of informedcitizens. When attemptingto cast optimal votes, the
strategiccitizen is concernedaboutproducinga policy-makingapparatusthat will,
in turn, produceoutcomesclosest to his or her ideal point. A state delegationthat
mirrorsone's ideologicalpreferenceis of little comfortto the informedvoter when
that delegationis partof a largerpoliticalstructurethat consistentlyproducespolicy in conflictwith that preference.
Fiorina (1992) recognized this point when developing his explanationfor divided government.His "modelof policy balancing"(Fiorina80) is premisedon the
notion that citizens are outcome-driven,and they recognize the input of both
elected branchesto those outcomes.4Curiously,Fiorina and his colleaguesopt to
exclude both the outcomeorientationand the role of the other elected branchesin
the processfrom their model of Senatedelegations.5
To assume that citizens are outcome-focused,ratherthan concernedonly with
the ideologicalbent of their state's delegation,makes the strategicvoting model
considerablymore complex. In addition to balancingthe influence of the state's
other senator,this highly sophisticatedvoter would have to evaluateother political
actors:the likelyideologicalcomplexionof the House of Representatives,the occupant of the White House, and the remainingmembers of the Senate. However,
these evaluationsoccur in an information-poorenvironmentsince the determination of the entire House, one third of the Senate, and occasionallythe president,is
simultaneous.As seen in figure 3, a moderatevoter would be well advisedto vote
for GOP Senate candidatesin both elections if that voter anticipatesa heavily
DemocraticHouse, Senate, and a Democraticpresident. In short, when we shift
our focus from the individual state's Senate delegation to policy outcomes, the
strategiccitizen model of ideologicalbalancingrequiressubstantiallygreaterinformationand evaluativeskills from voters.6
Though this work sees voters as interestedin "a balancedexecutive-legislative
package"(Alesina, Fiorina, and Rosenthal 1991, 29) a policy-outcome focus is
4Alvarezand Schousen (1993) find little empiricalsupport for the policy-balancingexplanationof
dividedgovernment.
5LikeFiorina,his colleagueshave demonstratedconcernfor outcomefocus and the role of all elected
branchesin their determination,though againthis was broughtto bear on the generaldivided government question and not the specific problemof Senate delegations.See Alesina and Rosenthal(1991).
61t is importantto point out that a shift in emphasisto policy outcomes yields expectationsthat are
fully consistent with the existence of mixed delegations.Single-issue voting is, we have argued,more
likely than the complex ideologicalcalculationsproposed.Since issues vary in saliencyover time, and
issue majoritiesare seldom congruent,we should fully expect that sequentialissue-orientedelections
would yield politicallyinconsistentoutcomes.
91
SequentialChoicesand PartisanTransitions
FIGURE 3
DISTRIBUTIONAL ASSUMPTIONS, ENHANCED EXPECTATIONS, AND
POTENTIAL OUTCOME DISTORTIONS IN THE STRATEGIC CITIZEN MODEL
M
DC
RC
RS
P HR S
DC-Democratic CandidateIdeologicalPlacement
RC-Republican CandidateIdeologicalPlacement
M-Population Mean IdeologicalIdealPoint
RS-Republican Sitting SenatorIdeologicalPlacement
HR-House of Representatives'AnticipatedMean IdeologicalPlacement
P-President's Anticipated(or estimated)IdeologicalPlacement
S-Senate's AnticipatedMean IdeologicalPlacement
consideredonly in a simple test to see if the partisancomposition of the entire
Senate is significantlyrelatedto the aggregateresults (it is not). The presidencyis
addressedonly in a midtermdummyvariable,and the House is ignoredaltogether.
Our secondpoint is that the model'sexpectationsof the electoratedo not fit well
with what we know about the abilities and behaviorof the Americanvoter (e.g.,
Converse1964 amongnumerousothers).Moreover,when our objectionsconcerning the need for an outcome focus are takeninto consideration,furtherraisingthe
cognitiveand informationaldemandson the votersin question,the model becomes
even more implausible.
Two Constituencies.The second generalexplanationis commonlyknown as the
two constituenciesthesis (Fiorina 1974;Bullock and Brady 1983; Shapiro,Brady,
Brody, and Ferejohn1990).Essentially,this argumentassumesthat each senatoris
elected by differentcoalitionsof voters, and it is to these specificcoalitionsthat the
senatorrespondswhen makingpolicy decisions.The assumption,of course,is that
each party enjoys about the same generalstrengthin the populace,againmore or
less normallydistributed.Each senatormodifieshis positionsonly slightly, falling
generallybetweenthe ideal points for their coalitionand the medianvoter position.
This slight shift allows the senatorto maintainhis or her party'sbase of support,
92
GaryM. Seguraand Stephen P. Nicholson
and simultaneouslyto appealto that small marginof voters aroundthe state mean
to providethe necessarymarginof victory.
Unlike the strategiccitizen model, this approachmakesno unrealisticassumptions aboutthe level of informationor cognitiveabilitiesof voters.Also, this model
anticipatesonly a smallmarginof nonideologicalswitchers,ratherthan the significant oscillationof sophisticatedvotersimpliedby the strategiccitizen model.
The two constituenciesthesis offers an explanationof electoralinstabilitybuilt
upon the existenceof two capableand competitivecoalitions.However,it does not
specificallyprovidea model of electoraloutcomes.We expect that the candidatesof
both the sitting senator'spartyandthe oppositepartywill adoptpositionsintended
to maintainpartysupportand to appealto the medianvoter.Absentthe advantages
of incumbency,thereis no reasonto assumethatthe candidateof the oppositeparty
is any more likely to win median voters than the candidateof the sitting senator's
party.This model, therefore,canexplainneithertransitionsto and frommixeddelegations,nor when-under these electoralconditions-mixed delegationswill exist.
We offer an explanationof transitionsthat is not reliantupon, but is consistent
with, a two-constituenciesportraitof the electorate.
RETHINKING THE PROBLEM
The two-constituencies thesis and the strategic-voterthesis are attempts to
explain apparentlyinconsistent choices made under identical circumstances.Of
course, institutionallydrivenexpectationsof senatorsshould not vary,and, ceteris
paribus,votersshouldbehaveconsistentlyin electingtwo people to the sameoffice.
Sequentialchoices in Senate elections are not, however,identical.In fact, given
the increasingdisintegrationof electoralpolitics, sequentialSenate elections are
of eachraceareimportantandmay
decreasinglyrelated.The politicalcharacteristics
varywidely acrosselections.While voters'policy preferences,expectationsof senators,and partisanshipmay not changeappreciably,the binarychoice-the candidatesthemselves,theircampaigns,and the surroundingpoliticallandscape-change
dramatically.In an eraof decliningpartisanshipand candidate-centeredcampaigns,
these changesare of criticalimportanceto voters. Transitionsto and from mixed
delegations,we argue,result directlyfrom the impactof these characteristics.
In short, we believe that the emergenceand disappearanceof mixed delegations
can be explainedby specific politicalcircumstances,are neither extraordinarynor
unpredictable,and are not the resultof unrealisticallysophisticatedbehavior.
POLITICAL FACTORS FACILITATING TRANSITIONS
Using all regularlyscheduledSenate elections from 1972 to 1988,7and building
on the workof Abramowitz,Jacobson,Squire,and others,we offera model built on
7One election, the 1976 Virginiaelection, is excluded due to the presenceof an incumbentthat was
not a memberof either majorparty.The election is not a transition.This reducesthe n to 299 and has
no appreciableeffect on the results.
SequentialChoicesand PartisanTransitions
93
long-identifiedpoliticalfactorsincluding four candidate-centeredvariables-candidatequality,short-termshocks,primaryelection results,and campaignexpenditures-and two contextual variables-political competitivenesswithin the state
electorateand the electoralcycle.
CandidateQuality.Jacobson(1990) arguesthat the qualityof the challenger,his
or her political experience, affects the outcome of any given House election.
Modest evidenceexists for a similareffect of challengerqualityon Senateoutcomes
(Abramowitz1988) and in voter informationlevels and evaluationsin Senate elections (Squire 1992). We expect, then, that differencesin the qualityof candidates
should be pivotalin predictinga transition.We arguethat the presenceof a highly
qualifiedchallengermay be sufficientto providea victorymarginto the candidate
of a partywith little historyof successin seekinga given seat.
Using a modifiedversionof Squire's(1988) coding for previouspoliticalexperience as a measureof quality,we test for the impactof candidatequalitydifferences
on the likelihoodthat an election will producea transitionin the partisancomposition of a Senatedelegation.8The relativequalitymeasureis the differencebetween
the incumbent'sscore(or incumbentpartycandidate'sscore when the seat is open)
and the challenger'spolitical experience score. The larger this difference, the
smallerthe chancethat the election will result in a transition.By incorporatingincumbentsinto this scheme, we also accountfor the differencesthat may occur due
to the absenceof an incumbentin open-seatelections.9
Short-TermShocks.The impact of political controversy,scandal,and reported
health problems on the electoral fortunes of the incumbent party is well documented (Abramowitz1988). For example, a confession of alcoholismby Herman
Talmadgein the 1980 Georgiarace and RogerJepsen's membershipin a "health
spa" which was later closed for prostitutionbefore the 1984 Iowa contest were
likely instrumentalin their defeats. For this reason, a dichotomous measure of
short-termfactors affecting the quality of the incumbent party candidate,coded
8Squire'sscheme is: Governor-6; House Member-5; State Official-4; State Legislator-3; Local
Office Holder-2; Other Political Position-1; no experience-0. Three changes were made. First, we
chose to eliminatethe weightingsystem Squire uses to assess the value of running for Senate as an incumbentofficeholderwith an existing constituencythat is part of the new constituency.The resulting
weights can give an enhanced,and we feel inappropriate,value to state offices such as treasureror insurancecommissionerover incumbentHouse members.Second, we attemptto accountfor public personalitiesseekingelectiveofficesince the namerecognitionassociatedwith their public personaeshould
be figuredinto the measureof quality.Likewise, people less familiarto the electoratebut well experienced in electoralpolitics presenta difficulty.We have chosen to code the astronauts,the notoriouscollege president,and the authorin the data, as well as formergovernorsand senatorsfrom neighboring
states,as threes,tryingto accountfor unusuallyhigh namerecognitionin the firstfour instancesand the
high degree of politicalexperiencein the lattertwo. Likewise, a formerpresidentialadviserand U.N.
ambassadorwas also coded as a three.
Finally, since our ultimatemeasureis comparative,we include incumbentsand code them as sevens.
9Informationon the politicalexperienceof each candidate,as well as scandalsand controversiesbeQuarterlyWeeklyReportelecsetting incumbentpartycandidates,was obtainedfrom the Congressional
tion roundupfor each year.
94
GaryM. Seguraand Stephen P. Nicholson
one for the presenceof politicalproblems,controversies,or health issues and zero
in their absence, has been included and should be a positive predictorof transitions. Informationregardingthe presenceof these factors-disastrous campaigns
for president, indictments,allegationsof improprieties,etc.-was obtainedfrom
the Congressional
Quarterly'spreelectionroundupswhich include descriptionsand
detailsof each race.
Primaries.A transitionin the partisancontrol of a Senate seat should be more
likely if the incumbentpartyis divided in its selectionof a candidate.Divisive and
hotly contested primarycontests are apt to reveal candidateor incumbentweaknesses, highlightissues likely to splinterthe incumbentparty'scoalition,and drive
down the eventualturnoutamongthe incumbentparty'svoters duringthe general
election(Abramowitz1988;Kenney and Rice 1984).For this reason,the percentof
the primaryvote receivedby the incumbentparty'snominee is included as a predictorof transitions,with the likelihoodof transitionincreasingas the primarypercentagefor the incumbent(or incumbentpartynominee)decreases.'0
CandidateFinances.The impact of money on congressionalelections is well
documented(e.g., Fenno 1982;Sorauf 1988;Jacobson1980, 1990, 1992). A better
financedchallengerpresentsa more formidableobstacleto the reelectionof any incumbent, and likewise should present the best opportunityfor a transitionin the
partisancompositionof a state'sSenatedelegation.
For each Senateelectionfrom 1972-1988, we recordedthe total funds dispersed
by each majorpartycandidatewho reachedthe generalelection, as reportedto the
Federal Elections Commission.As the ratio of challengerspending to incumbent
spending (or spending by the incumbent party's candidate)increases,we expect
that the likelihoodof a transitionto or from a mixed delegationwill also increase."
l
PoliticalCompetitiveness.
Significantattentionhas been given to the politicalheterogeneityor homogeneityof statesas an importantfactorcontributingto national
electoraloutcomes (Bullock and Brady 1983). This concept is at the heart of the
two constituenciesexplanation.
We use the absolutedifferencebetweenthe percentagesof a state'scongressional
delegation held by each party as a measure of its political competitiveness.The
measurecan take on a value from zero-meaning that each party holds the same
number of seats in the state's House delegation-to one hundred-indicating a
101nthe absenceof a primary,either due to the lackof an opponentor a caucus/conventionsystemof
nomineeselection,the incumbentpartynomineeis coded to have received100%of the vote. While this
approachglosses over the possibilityof continuingdivision within the party,it is likely that the deleteriouseffects of such low saliencedivisionarelargelymitigatedin the absenceof directprimaryelections.
IIThis calculationwas helpful in that it implicitlycontrolledfor state size, whereasa linearcombination of the two spending totals would have been problematic.The downside was the loss of two additionalobservations.In the 1976 Senate racein Wisconsin,Proxmirespent only $697 as comparedto his
opponent's$62,210, producinga ratiothat was enormous.In 1982,he spent nothing(at leastas reported
to the FEC), even while his opponentspent almost$120 thousand,makingthe valueof the financeratio
undefined.This lowersthe valid n to 297.
SequentialChoicesand PartisanTransitions
95
low degreeof competition,as evidencedby the completecontrolof that delegation
by one party.
To estimatethe relationshipbetween the competitivenessin the state electorate
and the likelihood of transitions,we need to control for the composition of the
existing Senate delegation.Dominationof the state by a single partyshould be directly related to the likelihood of a transitionif the challengeris of the state's
majorityparty, and inversely related if the challengeris of the state's minority
party.For this reason,we recoded the variable,multiplyingby -1 when the challenger is from the politicallydisadvantagedparty. This producesa politicalcompetitivenessvariablethat variesbetween -100 and + 100. Negative values indicate
that the challengerbelongs to a partythat capturesonly a minorityof House seats
and is thereforeless likely to win and producea transition;the converseis true for
positive values. A value of 0 indicates that the parties show approximatelyequal
strength in House elections.'2This variableshould be positively related to the
probabilityof a transition,regardlessof the electoralcircumstances.
ElectoralCycle.For whateverreason,the presidential/mid-termelectioncycle is
well recognizedas a significantpredictorof any party'schances in a generalcongressionalelection (Campbell1960;Kernell 1977;Jacobsonand Kernell 1981;and
Abramowitz1988). This cycle, therefore, should help explain transitionsto and
frommixed delegations.The winningpresidentialcandidateshouldhelp his or her
party win more votes for senatorthan the party might otherwiseexpect, and cost
copartisansvotes duringthe mid-termelection. In an electorallycompetitivestate,
those boosts and hindrancesmight accountfor enough variancein the vote to produce a transitionin the compositionof the state'sSenatedelegation.
In the model presentedbelow, electoralcycle is a dichotomousvariablecoded
as follows:presidentialelection year when challengerparty'spresidentialnominee
wins-i; presidentialelection year when challengerparty's presidentialnominee
loses-0; midterm election year when the challenger'sparty is in opposition-i;
midtermelection year when challenger'spartycontrolsthe White House-0. Electoralcycle should be a positive predictorof transitionssince it takeson the valueof
one when the outpartyis advantagedby the electoralcycle.
TESTING AND RESULTS
We estimatetwo models-a model of transitionsin generaland one that considers the partisan composition of the delegation before the election-thereby
specificallytesting the strategiccitizen model. The dependentvariableis a dummy
variablecoded 1 when an election leads to a partisanchangein the compositionof
the delegationto mixed or unified (indicatinga defeat for the incumbent party)
12Certainlyother measuresof partycompetitionare available.This particularmeasurecapturedour
interest in each party'sability to win elections to Congresswithin each state. Though small states are
prone to extremevalues, there is sufficientvariancein the dependentvariable-even at these extreme
values-that no distortionresults.Analysisof the residualsalso yields no evidenceof heteroscedasticity.
GaryM. Seguraand Stephen P. Nicholson
96
TABLE 1
LOGIT RESULTS FOR DELEGATION TRANSITIONS
IN U.S. SENATEELECTIONS:1972-1988
Predictor
Predictor
Constant
Candidatefinances
Candidatequality
Short-termshocks
Chi-square
Significance
% Predictedcorrectly
N = 297
.469
(.730)
2.57***
(.439)
-.065
(.073)
1.77***
(.560)
Primaryvote
Electoralcycle
Politicalcompetitiveness
-.052***
(.009)
.961**
(.377)
.526*
(.320)
146.63
.0000
84.2%
*Significantatp < .05; **significantatp < .01; ***significantatp < .001.
and 0 when the election has no effect on the partisanshipof the delegation.'3The
resultingnumberof cases, from 1972to 1988, is 297 elections.
PredictingTransitions
We test the impact of six variables,'4candidate-centeredand contextual,using
logit analysis.The unit of analysisis the individualregularlyscheduledSenatecontest.'5Table 1 presentsthe resultsfor the model.
13Thereis one case, Minnesotain 1978, wherethe electionresultsin the seat changinghandsbut, due
to a simultaneouschangein the otherseatvia a specialelection,the delegation'sstatusas unifiedremains
unchanged.Though here the electoratechose two senatorsof the same party,this case is still coded as a
transitionsince a seat changeshands. Coding it as a nontransitionor eliminatingthe case altogetherdo
not fundamentallyalterthe substantiveinterpretationof the findings.
140ne variablenoticeablymissing from the model is whetheror not the incumbentis a candidatefor
reelection.Transitionsare approximatelytwice as likely in open-seatelections when we controlfor the
relativefrequencyof each type of election.
We consideredincludingthis variablein the model but did not for both conceptualand methodological reasons.Since qualityis measuredas the differencebetweencandidates,and incumbencyis partof
this measure,inclusionof a second variablemeasuringessentiallythe same thing wouldbe redundantlikely resultingin multicollinearityproblems.Also, its inclusioncontaminatesthe resultsfor other candidate-centeredvariables.The reasonis simple:as borneout in a one-wayanalysisof variance,the mean
quality differenceis more than three times largerin elections contested by incumbents.Similarly,in
races in which there was no incumbent,the ratio of challengerspending to incumbentpartyspending
was more than twice that of racesin which there was an incumbent.
Including open seats and challengerquality, instead of our comparativequality measure, has no
significantimpacton the predictivepowerof the model nor the significanceof any of the remainingpredictors.
"5Withthe exceptionspreviouslynoted.
SequentialChoicesand PartisanTransitions
97
The results of the logit routineare highly consistent with our expectationsand
the model goodness-of-fittests easily meet the criterionfor significance.The percent of transitionscorrectlypredictedis 84.2 with the model performingsomewhat
better at predictingfailuresthan successes, as expected given the inherentlylarge
stochastictermassociatedwith these outcomes.The resultssupportour contention
that political variables,both candidate-centeredand contextual,can help explain
transitionswithoutresortingto sophisticatedvoter models.
Candidate-centeredvariablesare central to our explanationand are significant
predictorsof the probabilityof transitions.The variableCandidateFinances,critical
to the candidate-centeredage of politics, is highly significantbeyondthe .001 level.
The sign of the coefficientis positive which suggests that as the ratio of spending
increasesbetweenchallengerand incumbent,the probabilityof a transitionis more
likely.In most of the casesin which transitionsdid not occur,the ratioof challenger
spendingto incumbentspending was small (mean = .47). In contrast,the average
ratio of spending in elections where transitionsoccurred was greater than one
(mean = 1.40). Thus, when a transitiontakesplace, the challengeris likely to have
spent moremoney than the incumbent(or the candidateof the incumbent'sparty).
Two other candidate-centeredvariables,PrimaryVoteand Short-TermShocks,
are importantpredictorsin our model. Both exceed the .001 significancelevel and
the signs of their coefficients are in the predicted direction. The sign of the
coefficient for Primary Voteis negative, suggesting that the greaterthe level of
competitionan incumbent(or incumbentpartycandidate)facesin the primary,the
greaterthe probabilitythe candidatewill lose. The coefficientof the variableShortTermShocksis positive indicatingthat politicalcontroversies,scandals,and health
concernsadverselyaffect an incumbent'slikelihoodof reelectionand, in this instance,transitions.
Interestingly,we find no supportfor the impactof CandidateQualityon transitions. Althoughthe sign of the coefficientis negative,it is far from achievingstatistical significance.Although we can only speculateas to the reasonswhy candidate
quality did not affect transitionelections, these results might be attributedto the
relativelylargerstakesinvolvedin Senateelections.The high profileof Senatecandidatesmay compensatefor the low name recognitionand inexperiencedelectioneeringwhich dooms many "low quality"House candidates.'6
The contextualvariablesare importantpredictorsin the model as well. As expected, the variableElectoralCycleis highly significantbeyondthe .01 level and the
sign of the coefficientis positive. Therefore, if challengersare either of the same
party of a strong presidentialcandidate,or of the opposite party of an unpopular
16Analternative,of course, would be to use challengerqualityas a predictor.We chose our measure
becauseof its comparativenature,which accountsfor incumbencyand open seats. When substituted,
challengerqualityperformslittle better than our CandidateQualityvariable,similarlynever achieving
significance,and adds nothing to the predictivepowerof the model.
Multicollinearityis not a problem.This variablesignificantlycorrelateswith only the Financevariable, and then only at r = -.2475, well below the generallyacceptedlevel of tolerance.
98
GaryM. Seguraand Stephen P. Nicholson
president at the midterm election, they may have an advantage.Political Competitivenessis significantat the .05 level and the sign of the coefficientis in the hypothesized direction. This result suggests that the dominance of a state by the
politicalpartyopposite the incumbentmay increasethe probabilityof an electoral
defeat,and thereforea transition.
Transitions
to andfromMixedDelegations-A Testof the "Opposite
PartyAdvantage"
Evidencein supportof our alternativemodel is strong. Relianceon simple, and
well-established,contextual,and candidate-centeredpoliticalvariablesallowsus to
correctlypredict 84.2% of all transitions(incumbentparty defeats), both to and
from mixed delegations.
We are interestedif the predictivepower remainsrobust when we control for
whetherthe potentialtransitioncreatesa mixed delegationor signalsits demise.To
investigatethis question, we add an additionalvariableto the model-Delegation
Partisanship-which measureswhether the delegationbegins the election unified
(coded 1) or mixed (coded 0).'7
The additionof this variableallowsus to testthestrategiccitizenmodeldirectly.If
Alesina, Fiorina, and Rosenthal(1991) are correctin their finding of an opposite
partyadvantage,then we shouldlogicallyexpect the coefficienton this new variable
to be positive and significant,indicatingthat a unifieddelegationmakesan incumbent partyloss (and a transitionto a mixed delegation)more likely, given the electorate's alleged preferencefor the "oppositeparty." Similarly,the presence of a
mixed delegationwould reducethe likelihoodof an incumbentdefeatand a transition. Our findingsarepresentedin table2.
The parameterestimate for DelegationPartisanshipis insignificantlydifferent
from 0, lending supportfor our contentionthat the partisanshipof the other senator is of no consequence-in either direction-to the outcome of the election at
hand. Moreover,the inclusionof DelegationPartisanshipcausesvirtuallyno change
in the sign, magnitude,or significancelevels of the estimateson the originalvariables (the sole exception being the competitivenessvariablewhose p-value falls a
fractionto .053). The additionalvariablehas little effect on the predictivepowerof
the model since the percentpredictedcorrectlyremainsa robust83.8%.
But werethe parameterestimatereportedin table2 to havereachedsignificance,it
would still provideno supportfor the strategiccitizenmodel since the sign is in the
wrongdirection.Whatlittle relationshipexists seemsto indicatethatthe probability
of a transitionis higherwhen sucha transitionwouldresultin a unifieddelegation.In
short,wefind absolutelynosupport
for theexistenceof an oppositepartyadvantage.
17Analternativeapproachwould be to divide the populationinto two subsamplesand test the consistency of the model's performanceacrosstypes. We performedthis task and the results were generally
supportive,the model accuratelypredicting87.4% of outcomes when the delegationbegins the cycle
unified, and 83.2% when the delegationenters the election mixed. The method we choose to present
here is somewhatmore elegantand helpful in that it allowsus to test an additionalhypothesis.
99
SequentialChoicesand PartisanTransitions
TABLE 2
LOGIT RESULTS FOR DELEGATION TRANSITION
IN U.S. SENATEELECTIONS:1972-1988
Predictor
Predictor
Constant
Candidatefinances
Candidatequality
Short-termshocks
.657
(.764)
2.58***
(.443)
-.058
(.074)
1.84***
(.629)
Primaryvote
Electoralcycle
Politicalcompetitiveness
Delegationpartisanship
-.053***
(.009)
1.00**
(.384)
.516
(.323)
-.332
(.379)
147.52
.0000
83.8%
Chi-square
Significance
% Predictedcorrectly
N = 297
atp < .01; ***significantatp < .001.
*Significantatp < .05; "*significant
CONCLUSION
Transitions are not surprisinggiven the highly competitive nature of Senate
elections in the candidate-centeredera. In particular,challengerfinancinghad a
greatimpact on the probabilityof a challenger'ssuccess, and is a criticalfactorin
determiningthe probabilityof a transitionin either direction.Consistentwith the
findings of Abramowitz(1988), improprietiesare found to make transitionsmore
likely. Focusing on primaries,we find that an incumbentfacing seriousopposition
will be less likely to overcomeintrapartydivisivenessin a generalelectionwhich, in
turn, may well triggera transition.Finally, contextualvariables,includingboth the
election cycle and state political competitiveness,are significantpredictorsof the
probabilityof transitions.
Yet we find no supportfor the "oppositepartyadvantage."The partisanshipof
the other senatorhas no significantimpacton the probabilityof incumbentdefeat,
substantiallyundercuttingthe validityof the earlierproposition-that some voters
have a preferencefor mixed delegationsthat results in their increasedfrequency.
The strongresultsof our predictors,especiallythe candidate-centeredvariables,
offer a uniqueinsightinto the causesof dividedgovernment.As previouslyargued,
the mixed Senate delegationquestion has been viewed as more of an enigmathan
dividedgovernmentsince voter decisionsare (1) made sequentiallyfor (2) identical
officesby (3) identicalconstituencies.
We have broughtto this questionJacobson's(1990) hypothesisof "electoraldisintegration,"arguingthat outcomes of sequentialSenate elections in a candidatecenterederaare largelyunconnected.Our model successfullypredictsinconsistent
outcomesacrossa set of decisionsmadeby votersoperatingwith substantiallyfewer
100
GaryM. Seguraand Stephen P. Nicholson
uncertainties.In this context, the "electoraldisintegration"hypothesis operates
in a more demandingconceptualenvironmentthan the more generaldivided government question. Our results, then, serve as importantadditional support for
Jacobson'stheory.
Manuscriptsubmitted22 November1993
received6 May 1994
Final manuscript
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Gary M. Segurais assistantprofessorof politicalscience, University of California, Davis, Davis, CA 95616-8682.
Stephen P. Nicholson is graduatestudentin politicalscience,Universityof California,Davis, Davis, CA 95616-8682.