What does progress mean? What does victory mean? What does it mean for the Iraq government to be able to govern? How capable do Iraqi soldiers have to be before we can leave things in their hands?
This NY Times article explores that first question, noting that many Republicans have stated that they'll change their minds on the war if there's no progress by September. Of course, a cynic might say that they'll just point to some statistic - like murders by Saddam's secret police are down 100% - to justify continuing the war forever.
It is telling, however, that people are beginning to realize that without defining progress and victory we'll never be able to determine when it's time to leave.
Also, thanks to Rep. Jack Kingston (R-GA) for the metaphor, "Imagine trying to build a house without a ruler." Tape measure might've been more apt, but he's right that we're building one fucked up house.