But the politics in Congress have shifted in other ways in the past seven months; it's no longer enough for Petraeus to mollify critics by saying the surge is working.
Clinton (eager to change the subject this week) isn't ready to concede that point: "Let's remember what we were told about this surge a year ago: That the whole purpose of it was to give the Iraqi government space and time to do what it needed to do," Clinton told ABC's Robin Roberts on "Good Morning America." "That hasn't happened. . . . So clearly, the surge hasn't worked. . . . The point of the surge, its stated rationale, hasn't worked."
Obama is trotting out a new line -- saying McCain is endorsing a 100-year "occupation" of Iraq. He's already getting blowback from the RNC (out with a viewer's guide for the Tuesday hearings): "Replacing one dishonest attack with another is not the sort of 'new politics' voters are hoping for," spokesman Alex Conant said Tuesday morning.
But the candidates won't be the only hostile Democrats -- and they'll have the company of some frustrated Republicans.
"Unlike in September, when that news was fresh and the administration said a corner had been turned, even some of the war's strongest supporters in Congress have grown impatient and frustrated," Karen DeYoung writes in The Washington Post.
"Petraeus, the top U.S. military commander in Iraq, and Crocker will face many lawmakers who had expected more by now and who are wondering whether any real change will occur before the clock runs out on the Bush administration."
Democrats will seek to turn the issue against Republicans, by pointing out that while the surge has reduced violence, "it has not brought the war any closer to ending or reduced the costs of the conflict," the AP's Julie Hirschfeld Davis reports.
"With the economy eclipsing the war as voters' top worry, Democrats are putting more emphasis on the domestic and military side effects of the Iraq conflict, such as neglecting infrastructure investments at home, overstretching the military and losing sight of the al-Qaida threat."
Toss in some Iran, too: "Iran is emerging as a hot-button campaign issue, with the candidates differing sharply on what approach to take toward Tehran and its hard-line leadership," Yochi J. Dreazen and Laura Meckler write in The Wall Street Journal. "Focusing on Iran could be a double-edged sword for Sen. McCain, who is staking his campaign on his foreign-policy credentials and his belief that U.S. forces must remain in Iraq."
After the testimony is over, ABC's Terry Moran has an exclusive interview with Petraeus on Tuesday evening's "Nightline."
Clinton makes her appearance at a precarious moment for her campaign, with questions swirling about whether there's time for new strategists to put in place a new strategy. The new Quinnipiac Poll shows Clinton's Pennsylvania lead down to six points -- 50-44 -- inside the margin that will be considered an Obama victory, after her lead stuck in double-digit territory for months.
"The refurbished Clinton team faces challenges on two fronts: trying to contain fallout from union members and other blue-collar workers who are essential to her success, and seeking to persuade key supporters and donors that [Mark] Penn's removal can bring fresh energy," John Harwood and Jeff Zeleny write in The New York Times.