The Legal Philosphy of Justice Clarence Thomas: Necessary and Proper Clause, Constitution, Article I, Section 8, last paragraph.

The Necessary and Proper Clause is not a warrant to Congress to enact any law that bears some conceivable connection to the exercise of an enumerated power. Nor is it, however, a command to Congress to enact only laws that are absolutely indispensable to the exercise of an enumerated power. (Gonzales v. Raich, 545 U.S. 1, 57 (2005). Dissenting.