Diagramming the Preamble to the Constitution of the United States Here is our diagram of the Preamble to the Constitution of the United States. It is based on our understanding of the use of "in order to" as a subordinating conjunction that introduces a series of infinitival clauses (without subjects) that, in turn, modify the compound verbs "do ordain" and "establish." See A Grammar of Contemporary English by Randolph Quirk, Sidney Greenbaum, Geoffrey Leech, and Jan Svartvik. Longman Group: London. 1978. p. 753. We the People of the United States, in Order to form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defence, promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity, do ordain and establish this Constitution for the United States of America.