Worst Case

I was just listening to the news on Public Radio and a question came up about the new direction of the Iraq War that I thought was unusually naive. The question went something like this:
If the worst case does occur in Iraq, are the Iraqi forces strong enough now to handle it?
In other words, if civil war broke out in Iraq, would American troops wind up fighting it or have we trained the Iraqi police and army forces well enough for them to defeat a civil war?
Apparently, Rumsfeld feels that Iraq's security forces would handle it with a little help from their friends.
Someone correct me here if I'm wrong, but that seems to me like a really stupid question and here's why I say that. To me, the "worst case" in Iraq is when the forces we have trained join sides with sectarian forces and fight against each other, abandon whatever it is that the US is supposedly trying to accomplish and go on a rampage against each other in order to gain political strength through warfare.
Why is that not the "worst case" scenario in Iraq? Okay, yes I realize that the worst case really is if that happens and neighboring countries are drawn into the fight but that's not what we're discussing today. Today we are discussing civil war in Iraq, not an overall Middle East War. We'll save that discussion for later.
But if civil war in Iraq were to happen, how naive can a person be to imagine that the forces we have trained would ally themselves with us and not with their own people? Do we think our money is that important to these people that they would commit suicide just to defend "our" cause? How naive are we, anyway?