Article I, Section 9, clause 2, of the U.S. Constitution:
U.S. Const. art. I, § 9, cl. 2.
Article III, sections 1 through 2 of the U.S. Constitution:
U.S. Const. art. III, §§ 1–2.
Q: How do I cite the U.S. Constitution as a whole?
A: Generally, you don't. When citing the Constitution, cite the specific pieces you are using, instead of the whole document. APA style explains that when referring to a whole constitution, indicating the constitution in the narrative is sufficient:
"The U.S. Constitution has 26 amendments."
Article and amendment numbers are given in Roman numerals (I, II, III); section and clause numbers are given in Arabic numerals (1, 2, 3).
For state constitutions, use the abbreviated name of the state:
N.C. Const. Ariz. Const. etc.
When citing a provision that has been amended, add the date it was amended in parentheses.
For APA and MLA style, this would be the reference entry, and for Chicago style this would be the footnote:
U.S. Const. amend. XVIII (repealed 1933)
APA / MLA in-text: ( U.S. Const. amend. XVIII, repealed 1933)
On the treatment of reference list / bibliography entries:
APA and MLA style both require reference list entries and in-text citations for specific pieces of constitutions. The formatting is generally the same for both reference list entries and in-text citations.
When using only a handful of legal citations in Chicago style, the recommendation is to limit legal citations to the text itself, using narrative to include information that would have gone in the footnotes. However, when using several legal documents in Chicago style, supplement with footnotes.
Chicago style requires only footnote citations for legal documents. The documents do not need to be listed in the bibliography.