No, the government has to have a positive and compelling reason for interfering with the private lives of citizens. "I don't like druggies" is insufficient.
If Tom’s argument was “it doesn’t matter that drugs are bad, we have no constitutional authority to stop them”, then your response to me would be a good one.
But Tom was arguing that “we haven’t won the war, so we should surrender”, and for THAT argument my response is that you don’t surrender simply because your current approach isn’t working, you stop the war if there is no good reason to WANT to win the war.
BTW, regardless of whether drugs can constitutionally be criminalized, I think the government has EVERY RIGHT under the constitution to be CONCERNED about illegal drugs. There are things government can do short of making something illegal, and I don’t think many of the “legalization” supporters are saying government should simply eliminate all the laws on the books about drugs.
If it would be OK with you constititutionally for government to regulate, control, and tax drugs, then you are saying government has a legitimate concern about the issue.