If the Democrats had held their ground, one of two outcomes would have happened
1. War ends middle of next year at the latest
2. Bush blatantly acts in defiance of Congress
Obviously #1 would be the best option, but #2 isn't going to be good for the Republicans instead.
Now that this Congress has shown that they fold against Mr. 28%, we're going to have to wait until January 20, 2009 to start a withdraw process, that if we're lucky will complete by the middle of 2009.
This just extended the war by AT LEAST 1 year, possibly many. Bush gets to do whatever he wants in Iraq for the remaining 20 months of his Presidency. Huge victory for Bush. Huge defeat for America.
How does stopping a supplemental funding bill, that largely pays for the "surge" bring an end to the war any faster? It seems fairly theatrical to suggest it would. If the Dems really want to end the whole thing they will need to either deauthorize the war (which isn't going to happen) or cut the actual funding (not a supplemental) in up coming fiscal year.
Keeping it real - I don't think the Dems want to be responsible for the chaos that would result from simply defunding or deauthorizing the war. They want a new direction (for the most part - the Dems are far from a unified front on any issue - this one not being an exception) not a mess. To get that, Bush either has to change his mind (which isn't going to happen without long term pressure building on the GOP - and maybe not even then) or a new President has to take office.
I took a moment to surf some of the more Democrat leaning web sites - and the number of folks pitching fits about this and cursing their own party was quite surprising to me. The expectations of these folks has out stripped any achievable outcome completely.