WASHINGTON — One of the Obama administration’s key allies in Congress, Senate Foreign Relations Committee Chairman John Kerry (D-Mass.), is breaking with the president on Afghanistan and saying the strategy in the war needs to be revised. The development, coming from someone who was once a strong backer of Obama’s decision to increase troops in Afghanistan, could deal a significant blow to support for the administration.

“What I don’t want is to be party to a policy that continues simply because it is there and in place,” said Kerry in an interview with the Boston Globe about his evolving views on the war. “That would be like Vietnam. And that is what I am determined to try to prevent.”

Kerry, according to the Globe, is calling for “a more limited focus and fewer American troops than the 155,000 that are in place now.” In the coming months, the Senate Foreign Relations Committee will be holding a series of oversight hearings on the Obama administration’s strategy.

“Obviously, I think progress has been made in military terms, but everybody agrees there is not a military solution,” Kerry said. “What I worry about is whether or not the governance [improves] sufficiently to make a difference.”

Kerry isn’t alone in his concerns. Sen. Richard Lugar (R-Ind.), the ranking Republican on the committee, recently told reporters that many Americans are increasingly getting frustrated with the war and are going to have to decide whether they want to continue spending billions of dollars for many years to come.

“For ordinary Americans looking at all this, they wonder, where does this stop?” said Lugar. “Here, American taxpayers have been generous. Billions of dollars are going to Afghanistan to try to improve the standard of living of people, apart from the military side. But we’re running into real problems with regard to Afghan law and administration, and even humanitarian matters.”

The Afghanistan war has not, unlike the Iraq war, had a figure equivalent to the late Rep. John Murtha (D-Pa.), a conservative Democrat with strong national security credentials and ties to the military who became an outspoken critic of the war. Several observers have said that Kerry could possibly have the same impact if he took up that mantle, in large part because of his record in Vietnam.

“Afghanistan now awaits its Fulbright,” wrote Katrina vanden Heuvel, editor of The Nation, in The Washington Post, in December. “It is time for the Senate to make an independent review of the war, and to challenge — as Sen. J.William Fulbright did during the Vietnam war — a president unwilling to end a conflict he knows will not be won. Surely, it is fate that the chairman of the Senate Foreign Relations Committee is Sen. John Kerry. Nearly 40 years ago, as a brave, decorated, young Navy lieutenant returning from Vietnam, he challenged senators to do their duty, saying that each day ‘someone has to give up his life so that the United States doesn’t have to admit something that the entire world already knows…that we have made a mistake. … How do you ask a man to be the last man to die for a mistake?’”

Kerry,however, told the Globe that he doesn’t think Afghanistan is the same as Vietnam. “Some people try to make it [Vietnam] and some people want it to be the same exercise,” Kerry said. “But it just isn’t. Unlike Vietnam, where there was no threat to the United States, and no real strategic interest — it was trumped up — here there is a real one.”

He said though that he is applying many of the lessons from that war to the current conflict. “Don’t take things for granted,” he added. “Don’t take things at face value. Don’t believe everything somebody tells you because they are in a position [of authority]. Probe it. Look at it. Test it. Look for the truth. It took us too long to get to the truth in that war.”