[simonh]

Other legal methods could absolutely have been used at the time, making it a constitutional amendment was a tactic. The idea was to make it difficult or impossible to challenge or repeal. If it was a medical regulation, that could just be changed by a later administration. A law might be challenged before the Supreme Court. A constitutional amendment insulated it from Supreme Court oversight and made it much harder to overturn legislatively.

[sjy]

It was not really a tactic, they didn’t believe the federal government had the legislative power to effect prohibition without it: https://history.stackexchange.com/questions/1201/what-were-t...