phased pulout vs. Troop increase

So whats the the best strategy. It's obvious that 'stay the course' hasn't been working. I can see how the democrats think we should leave, but in all honestly i think if we start to pull out now, iraq is gonna explode. It's going to be a humanitarian crisis. I don't know if troop increase is the solution, but we can't just leave now. The iraqi government is simply too weak, the iraqi army too. Im a leftist myself and against the invasion of iraq in the first place, but goddamn if we leave iraq now it will be chaos.

okay let's say the united states withdraw from iraq and shortly after the government gets toppled by the opinion of the majority and it becomes an "islamic fascist haven". what harm will that do the united states?