They were never for it, because it is useless and a waste of money. They have voted for bills that included funding for it in the past in exchange for other things.
You think the wall is important? Let’s hear your offer for it. I want mass increases in immigration across the board and a mass legalization of DACA people. Deal?
Why would it be a huge mistake?
Clinton, Schumer and others have voiced support for border barriers in the past. They have also supported stopping illegal aliens in the past...
I think that immigration levels are high enough. I do agree that they should settle the DACA by allowing the current DACA people to stay and become citizens through normal channels.
If you cut the military budget it half it would cause a huge impact to the world economy and effect many countries. This would be due to the contraction of military forces back to the US and closing of overseas bases and installations. Other countries would have to step up their game as they should anyway to fill the global protection void.
I am not opposed to a gradual reduction, but half or more is quite a bit too much.