Article I, Section 8, Clause 18:

[The Congress shall have Power . . . ] To make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers, and all other Powers vested by this Constitution in the Government of the United States, or in any Department or Officer thereof.

In general, Supreme Court doctrine has afforded relatively little attention to whether the word “proper” as used in the Necessary and Proper Clause independently limits Congress’s authority.1 Indeed, it is not clear that “proper” imparts any limitation on Congress’s power beyond the McCulloch test itself, which requires a law to both be “appropriate” and “consist[ent] with the letter and spirit of the constitution.” 2 At the least, to be “proper,” an act of Congress must not violate another express or implied constitutional provision, including the system of dual state-federal sovereignty established by the Constitution.3 For example, the Court has held that the Tenth Amendment operates to restrain the scope of the Necessary and Proper Clause, holding that an otherwise valid law that violates principles of state sovereignty is not a “proper” exercise of federal power.4

Footnotes

1

See Gary Lawson & Patricia B. Granger, The “Proper” Scope of Federal Power: A Jurisdictional Interpretation of the Sweeping Clause, 43 Duke L.J. 267, 285 (1993) ( “Historically, discussion of the [Necessary and Proper] Clause has been dominated by discussion of the meaning of the word ‘necessary.’ . . . The word ‘proper’ has generally been treated as a constitutional nullity or, at best, as a redundancy.” ).

2

See United States v. Comstock, 560 U.S. 126, 160–61 (2010) (Thomas, J., dissenting) (brackets in original) “The means Congress selects will be . . . ‘proper’ if they are not otherwise ‘prohibited’ by the Constitution and not '[in]consistent’ with its ‘letter and spirit.’” (citing McCulloch v. Maryland, 17 U.S. (4 Wheat.) 316, 421 (1819)).

3

See Buckley v. Valeo, 424 U.S. 1, 135 (1976) ( “Congress could not, merely because it concluded that such a measure was ‘necessary and proper’ to the discharge of its substantive legislative authority, pass a bill of attainder or ex post facto law contrary to the prohibitions contained in § 9 of Art[icle] I. No more may it vest in itself, or in its officers, the authority to appoint officers of the United States when the Appointments Clause by clear implication prohibits it from doing so.” ); New York v. United States, 505 U.S. 144, 166 (1992) ( “We have always understood that even where Congress has the authority under the Constitution to pass laws requiring or prohibiting certain acts, it lacks the power directly to compel the States to require or prohibit those acts.” ).

4

See, e.g., Printz v. United States, 521 U.S. 898, 924 (1997) ( “When a ‘La[w] . . . for carrying into Execution’ the Commerce Clause violates the principle of state sovereignty reflected in [the Tenth Amendment and other constitutional provisions] it is not a ‘La[w] . . . proper for carrying into Execution the Commerce Clause.’” ).