While liberal Democrats — led by House Speaker Nancy Pelosi (D-Calif.) — have voiced discontent over the past few days over Obama’s 50,000 troop commitment in Iraq, top Republicans are embracing the troop announcement today.

Sen. John McCain (R-Ariz.) took to the Senate floor to declare “the president’s withdrawal plan is a reasonable one.” Senate Minority Leader Mitch McConnell (R-Ky.) commended “the president’s decision yesterday for making it possible to take another step toward realizing our goal of a stable Iraq.” Rep. Eric Cantor (R-Va.), the House GOP whip, said Obama “deserves credit for not listening to the chorus of voices calling for a rapid drawdown of forces.”

And House Minority Leader John A. Boehner, who has presided over a unified opposition party in the House, praised the Iraq plan.

“The plan put forward by President Obama continues our strategy of bringing troops home from Iraq as they succeed in stabilizing the country,” Boehner said. “I believe he has outlined a responsible approach that retains maximum flexibility to reconsider troop levels.”

There was one catch in the Republican embrace of Obama’s troop withdrawal plan — several of them referred to it as the “Petraeus plan,” sending the message that they believe Gen. David Petraeus — and by extension former President Bush — were right on Iraq.

“It is encouraging to see the Obama administration embrace the plan of Gen. David Petraeus that began with the successful surge in 2007,” McConnell said.

Other Republicans had a bit of “I told you so” in their reaction to Obama’s announcement.

“I appreciate that President Obama has signaled his willingness to revisit his strategy if conditions on the ground change,” said Rep. Joe Wilson, a conservative South Carolina lawmaker.

To be sure, in his address to Marines at Camp Lejeune, N.C., Obama framed his Iraq plan as perfectly in sync with his campaign promise.

“As a candidate for president, I made clear my support for a timeline of 16 months to carry out this drawdown, while pledging to consult closely with our military commanders upon taking office to ensure that we preserve the gains we’ve made and protect our troops,” Obama said. “Those consultations are now complete, and I have chosen a timeline that will remove our combat brigades over the next 18 months.

“Let me say this as plainly as I can: By Aug. 31, 2010, our combat mission in Iraq will end.”

But it’s the residual force of up to 50,000 that twists the stomachs of Democrats who wanted a faster withdrawal.

Rep. Lynne Woolsey (D-Calif.), a co-founder of the Out of Iraq Caucus, said “50,000 residual troops is unacceptable.”

“I have long been for a significant drawback of troops in Iraq,” Senate Majority Harry Reid (D-Nev.) said in a Thursday news conference. “Fifty-thousand is a higher number than I anticipated.”

Democrats aren’t just worried about the short-term withdrawal; they’re concerned about a permanent presence.

“I think that’s a lot of troops, and I would prefer to see him draw that down further,” said Sen. Byron Dorgan (D-N.D.). “Because you know what happens: As was the case with Korea, they just stay there forever and there’s an enormous burden on this country to pay for troops stationed abroad. To the extent that we can, I’d like to see a drawdown that’s more than the 50,000 level.”

Rep. Dennis J. Kucinich (D-Ohio), a leader in the anti-war movement, was harsh: “You cannot leave combat troops in a foreign country to conduct combat operations and call it the end of the war. You can’t be in and out at the same time.”

And Democrats such as Dorgan and Kucinich probably didn’t see this coming in the first 100 days of the Obama administration: McCain talking about how good Obama’s Iraq plan is.

“The president’s plan, as it was briefed yesterday, is one that can keep us on the right path in Iraq,” McCain said.