FiveThirtyEight.com looks at pot legalization polls

He ends his informative post with this:

My guess is that we'll need to see a supermajority of Americans in favor of decriminalizing pot before the federal government would dare to take action on it. If the upward trend since 1990 holds (and recall my earlier caution: it might not), then legalization would achieve 60 percent support at some point in 2022 or 2023. About then is when things might get interesting.

You should go read the whole thing.