Because he knows no other way

We can argue over whether McCain really meant that Americans should be dying in Iraq for 100 years or whatever, but I think this is an excellent plain-english translation of what McCain actually meant:

McCain's wants to stay in Iraq until no more Americans are getting killed, no matter how long it takes and how many Americans get killed achieving that goal —- that is, the goal of not getting any more Americans killed. And once that goal is achieved, we'll stay.

All to secure that precious, precious oil freedom.