Petraeus today:

“None of this will be rapid,” Lt. Gen. David Petraeus told the Senate Armed Services Committee. “The way ahead will be neither quick nor easy.”…
“The situation in Iraq is dire. The stakes are high. There are no easy choices. The way ahead will be very hard. … But hard is not hopeless,” he said…
Asked by McCain how soon he thought he would know whether the new strategy was working, Petraeus said, “We would have indicators at the least during the late summer.” As currently planned, he said, the last of the five additional U.S. Army brigades would be ready to fight in Baghdad by the end of May….
Sen. Edward Kennedy asked him why an extra 21,500 would make a significant difference.
Petraeus replied that the important factor was how extra troops are used, not their numbers. Their main focus, he said, will be on securing the civilian population of the capital rather than killing insurgents…
He told the Senate committee that he believes ethnic divisions in Iraq are not as severe as in Bosnia, where U.S. and NATO forces intervened in the 1990s to stop a civil war. He noted, however, that Iraq’s divisions got worse in 2006.