GATES AND LEON
Cases
Under
Aguilar-Spinelli
Under Gates
(1983)
Under Gates
(1983) and
Leon (1984)
Officer
Magistrate-Judge
(deciding whether to issue a
warrant)
Investigates
case.
Determines pc, keeping prongs
separate.
Presents
affidavit
with facts
sufficient to
show pc.
Prongs:
Investigates
case.
Determines pc, under totality of
circumstances.
Presents
affidavit
with facts
sufficient to
show pc.
Given all the circumstances,
including the “veracity” and
“basis of knowledge” of persons
supplying hearsay information,
is there a fair probability that
contraband or evidence of a
crime will be found?
Investigates
case.
Determines pc, under totality of
circumstances. Magistrate
solely responsible for assessing
pc.
Presents
affidavit with
facts suffic. to
show pc, but
magistrate is
responsible for
pc
determination
a: validity/basis of knowledge
b: veracity
--credibility or
--reliability
Given all the circumstances,
including the “veracity” and
“basis of knowledge” of persons
supplying hearsay information,
is there a fair probability that
contraband or evidence of a
crime will be found?
Reviewing Judge
(deciding a
suppression motion)
Determines whether
Magistrate had a
substantial basis for
concluding that pc
existed, considering
prongs separately.
If no substantial basis
for pc, suppress.
Determines whether
Magistrate had a
substantial basis for
concluding that pc
existed under totality
of circumstances.
If no substantial basis
for pc, suppress.
Determines whether
Magistrate had a
substantial basis for
concluding that pc
existed under totality
of circumstances.
If no, asks whether
officers acted with
objective good faith.
If no, suppress.
Note that Leon formally divides responsibility between magistrate-judge and officer.