Why didn't federal drug prohibition in America require a constitutional amendment?

[BigBlueBox]

During the 1970s, the Controlled Substances Act and other laws placed restrictions on several drugs. No constitutional amendment was required to pass these laws. This in stark contrast to alcohol Prohibition earlier in the century, which required the 18th amendment to be passed. Why did alcohol Prohibition require a constitutional amendment, but not drug prohibition?

 

[David T]

The Commerce Clause was interpreted much more narrowly at the time of Prohibition than at the time of the War on Drugs. if Wickard v. Filburn had been the law in the 1910's no constitutional amendment would have been required to institute alcohol prohibition: https://en.wikipedia.org/wiki/Wickard_v._Filburn

 

[BigBlueBox]

The Commerce Clause was interpreted much more narrowly at the time of Prohibition than at the time of the War on Drugs. if Wickard v. Filburn had been the law in the 1910's no constitutional amendment would have been required to institute alcohol prohibition: https://en.wikipedia.org/wiki/Wickard_v._Filburn

Interesting. I had a feeling that it involved a more permissive interpretation of the interstate commerce power. Was the Supreme Court's gradual strengthening of federal power at the expense of state power related to the fact that Supreme Court judges must be confirmed by the Senate, and senators became directly elected instead of chosen by state legislators in 1913?