I would have to say that the debate over this issue was settled in the 2004 election when W won re-election.
I point to illegal immigration being the forfront issue for '06 and '08.
Basically, I contend that the American left shot the wad with " no WMD" and "Bush lies" trying to oust W in 2004. They missed their target by a mile and they are out of amunition.
I predict that the left will finally 'admit' that opposition without solution has failed them and they will turn to the illegal labor force for votes to take control of anything they can get their hands on in the next two elections. But I also predict they will fail as miserably as they have since 2000.
as long as any war is going on, it can be a very tricky political issue. i can remember lyndon johnson massacre barry goldwater (in large part on war-related fears); then mccarthy, the peace candidate challenged johnson in the NH primary, and scared lbj out of the race. nixon won the general election as a peace candidate.
truman had some problems because of the korean war. (the repubs were for ending it.)
public opinion can turn really fast if a war becomes unpopular. that's why the wma issue is still important.