Correct, there are many federal parks in DC where this would not apply. Even on DC land, I don't think the law permits smoking in public anyway.
I don't think Congress will veto the law (which doesn't happen often) but I think there's a good chance they kill it with a budget rider (which happens every year).
Re:Alaskans vote to legalize marijuana
by goatforce5 on Wednesday November 05, 2014 @11:00AM
(#8562385)
It will be interesting to see if they choose to enforce it on federal lands.
I don't think Congress will attempt to shut it down in the city. I don't see that being a winning move politically, for a number of reasons. But I could also see zero tolerance being stepped up on The Mall to keep the tourists from less tolerant states placated.