That clause empowers Congress to enact "all Laws which shall be necessary and proper for carrying into Execution" its enumerated powers.

WSJ: Barnett and Foley: The Nuts and Bolts of the ObamaCare Ruling

For this reason, the mandate also cannot be justified under the Necessary and Proper Clause, because that clause can effectuate only those powers that Congress actually possesses under the Commerce Clause, not create new ones.

FORBES: Obamacare Insurance Mandate - Another Circuit Heard From

As the Supreme Court has repeatedly explained, the Necessary and Proper Clause does not expand the scope of Congress's enumerated powers.

WSJ: Barnett and Foley: The Nuts and Bolts of the ObamaCare Ruling