Is the number of Senate Republican defectors from President Bush's Iraq strategy about to rise? Probably, but not in a way that would bring an end to the war anytime soon.

The recent public comments of two senators who have been stalwart allies of the president caused murmuring in Republican circles that Bush's congressional support is about to erode. On May 25, hours after Congress sent a war funding bill without a timeline for withdrawal to Bush's desk, Senate minority leader Mitch McConnell said in a press conference that "the handwriting is on the wall that we are going in a different direction in the fall, and I expect the president to lead it. . . . I think we are looking for a new direction in the fall."

Then, less than 48 hours after McConnell's remarks, Alabama senator Jeff Sessions told CBS News, "By September, when General Petraeus is to make a report, I think most of the people in Congress believe, unless something extraordinary occurs, that we should be on a move to draw those surge numbers down." A top GOP senator told me last week he estimates up to a third of the 49 Senate Republicans are nervous about developments in Iraq and may move from Bush's position come fall. Meanwhile, an "influential Republican strategist" told National Review Online that up to half of the Republican Senate caucus could vote against Bush on future war appropriations if there are no improvements in Iraq by September.

That's when Gen. David Petraeus, the commander of Multi-National Force-Iraq, plans to return to Washington and update Congress and the American public on the conduct of the war. The timing of the September report is somewhat arbitrary. According to Coalition sources, it was in January that Petraeus decided on late summer or early fall as the best time to assess the new strategy, the foremost goal of which is the security of the Iraqi people. The assessment will be comprehensive, examining Iraqi security, governance, economics, and the rule of law. It will be done in cooperation with the U.S. embassy in Baghdad and Ambassador Ryan Crocker. It will sketch various potential courses of action and speculate on the likely consequences of each. But any decision on which course to follow will be made by policymakers in Washington.

Petraeus, Crocker, and Defense Secretary Robert Gates discussed the idea when the secretary visited Iraq in mid-April. Gates was receptive. The following week Petraeus visited Washington, where Congress was in the midst of passing a supplemental appropriations bill for Iraq that included a timetable for American withdrawal. During a press conference at the Pentagon, Petraeus mentioned the decision to report on the war's progress in September. The media and political class immediately seized on September as a turning point. Republicans kept telling everyone to give the surge "till September." They never said what would happen afterward.

That's probably because no one knows what will happen. Chances are, if the level of violence in Iraq has not been reduced by the time Petraeus makes his report, more Republicans will jump ship. A member of the Senate Republican leadership says the GOP caucus is uniformly disappointed with the inability of the Iraqis to pass legislation that could lead to political reconciliation. Congress included language in its latest Iraq appropriations bill that would penalize the Iraqis if they do not meet certain "benchmarks," while also giving Bush the power to waive those penalties. The author of the benchmark language was Virginia Republican John Warner, the ranking member of the Armed Services Committee who is considering a move away from the president. Warner is up for reelection next year.