To avoid charges of plagiarism I credit this guy

Libertarians ignore the clear intention of
The Founders to erect a national government that did not previously
exist, and vest it with powers that are ample, extensive, strong, and
supreme, in order to preserve the Union. They rejected laissez-faire
capitalism in favor of national government regulation of interstate,
foreign nation and Indian tribe, commerce. The Founders believed this
was absolutely necessary to preserve the Union. I see alot of references
that don’t list this among the powers of the national government. You
can’t consider yourself a supporter of The Constitution and pretend that
very important grants of power in Article 1, Section 8, don’t exist.