From time to time, we will run excerpts from columnist Dick Polman's blog, "Dick Polman's American Debate." Watch this page for Polman high points - and check out the blog.

Here's an interesting new quote from Capitol Hill: "We need to get out of the combat business in Iraq," by setting a time line for U.S. troop withdrawal, in accordance with the recommendations of the bipartisan Iraq Study Group.

Surely this must be a defeatist Democrat who has sold his soul to moveon.org, right? Nope. The senator who uttered those remarks Thursday was none other than Sen. Lamar Alexander (R., Tenn.) - a heretofore loyal Bushie on Iraq.

Meanwhile, we now have Sen. Olympia Snowe (R., Maine), working up a bill that would require President Bush to roll back U.S. troop levels to pre-surge numbers if the Iraqi government fails to meet specific benchmarks of progress.

Meanwhile, even House Minority Leader John Boehner (R., Ohio) is saying that rank-and-file Republican patience is likely to run out by early autumn. As he put it the other day, "By the time we get to September, October, members are going to want to know how well this [surge] is working, and if it isn't, what's Plan B?"

Boehner was later seconded by Sen. Susan Collins (R., Maine), who is up for reelection next year in a state where antiwar fervor is now reportedly strong.

Last week, we also learned that a delegation of elected Republican moderates had trekked to the White House to perform a task that once was deemed unthinkable: Piercing the Bush bubble and telling the president to his face that it was past time for him to start dwelling in the real world, to recognize the wreckage of his credibility, to grasp the fact that most Americans wanted him to be held accountable for his failures - and to understand that further intransigence on Iraq might well wreck the Republican Party in 2008. One congressman reportedly told Bush, "My district is prepared for defeat."

I, as well as many other observers, have argued all along that the top political story this year would be the potential willingness of beleaguered congressional Republicans to liberate themselves at last from Bush fealty, to grasp the fact that Bush has been driving them over a cliff, and to communicate these concerns to Bush in an effort to force a change of course in Iraq. This finally appears to be happening; barring an unlikely miracle in Iraq, the trend can only accelerate.

GOP moderates are seriously imperiled in 2008; they tend to represent states and districts where antiwar sentiment is strong. It's noteworthy that the meeting with Bush was organized by House Republicans from Illinois and Pennsylvania (key states in the '08 presidential race), and that even a congressman from Virginia (an increasingly competitive state) felt compelled to tell Bush that, in one section of his district, he estimated that support for the President had fallen to 5 percent.

On the Senate side, meanwhile, four Republicans are thought to be vulnerable in 2008: Collins, John Sununu of New Hampshire, Gordon Smith of Oregon, and Norm Coleman of Minnesota. Another, Wayne Allard, is vacating his seat in a state (Colorado) that has been trending Democratic. . . .

Naturally, there are still some Bush defenders who think that the revolt of the moderates is either no big deal or simply irrelevant. Conservative commentator John Podhoretz writes that the delegation of 11 moderates who met with Bush constitutes only 5 percent of all the Republicans serving in Congress. (Quiz for Podhoretz: How many congressional Republicans went to the White House in August 1974 to tell Richard M. Nixon that he had lost his party's support on Watergate? Answer: three.)

And it's Vice President Cheney (no surprise) who thinks that the moderate revolt is irrelevant, compared with the importance of the glorious American mission in Iraq. As he told Fox News, "We didn't get elected to worry just about the fate of the Republican Party."

The reality, however, is that, beginning this autumn, Bush and Cheney may find it difficult to prosecute the war as they see fit. If the war is still going badly, and if Gen. David Petraeus fails to deliver a credibly sunny forecast, a sizable number of vulnerable Republican incumbents might bail out on Bush (and vote with the Democrats for a change of course) in an effort to save their political hides. That might not be the most enlightened rationale for winding down the U.S. combat role, but, at this point, a landslide majority of the American people would welcome any motivation for doing so.

Contact Dick Polman at dpolman@phillynews.com. See his blog at http://go.philly.com/polman.