WASHINGTON — Osama bin Laden's death could force President Barack Obama to change his strategy for ending the nearly decade-long Afghan war, including keeping tens of thousands of U.S. troops in Afghanistan at least until 2014, according to some Western experts and officials.

The key rationale underpinning Obama's strategy — repeated in every major statement that the president or his lieutenants make on the war — is that the massive U.S. troop presence is required to stop the Taliban from retaking power in Afghanistan, which could allow al Qaida to use the country again as a sanctuary from which to attack the United States.

But bin Laden's death on Sunday in a U.S. commando raid on a compound in northeastern Pakistan dealt a huge blow to al Qaida that will almost certainly fuel domestic opposition to the war, some officials and experts said. Polls show that more than 60 percent of Americans oppose the war.

"With al Qaida taken down a big notch, how are we going to sell what we are doing?" asked a veteran U.S. diplomat, who asked to remain anonymous in order to speak freely. "I wouldn't be surprised to see policy shifts" after Army Gen. David Petraeus relinquishes command of U.S.-led forces in Afghanistan this summer.

"The American people are going to be pretty quick to write the obituary of al Qaida because bin Laden is dead," said Christine Fair, an expert at Georgetown University, who warned that doing so "is premature" because the terrorist network remains a threat.

One key pillar of Obama's strategy is already facing an uncertain future as a result of bin Laden's death: the billions of dollars in U.S. aid that Pakistan receives in return for cooperating in fighting terrorism and closing the havens that the Afghan Taliban and allied groups maintain inside its borders.

Key lawmakers indicated on Tuesday that Congress could slash the $3.1 billion the administration is seeking in 2012 for Pakistan if it is determined that the Pakistani army or spy agency, the Inter-Services Intelligence Directorate, were complicit in hiding bin Laden outside the city of Abbottabad.

"I think we have to know whether they (the Pakistanis) knew. If they didn't know, why didn't they know? Was this just benign indifference or indifference with a motive?" said Senate Intelligence Committee Chairwoman Dianne Feinstein, D-Calif.

Suspicions of Pakistani complicity were fueled by charges that the ISI has been secretly backing the Afghan Taliban and allied groups in a bid to put a government in Kabul that favors Pakistan over its foe, India.

Pakistan denies the allegations and disavows knowing that bin Laden's hideout was in an area filled with military facilities and retired officers, 35 miles by air from Islamabad, the capital.

The White House said Tuesday that bin Laden's killing was consistent with its strategy, under which U.S. troops will begin withdrawing in July and Afghan forces, who are being trained in greater numbers, will gradually assume greater security responsibilities before taking over the entire country by 2014.

"The president's plan is on track," said White House spokesman Jay Carney. "And the focus of that operation, of the . . . U.S. personnel in Afghanistan, is on al-Qaida."

Yet senior U.S. intelligence experts estimate that there are fewer than 100 al Qaida fighters in Afghanistan at any time. And the unprecedented level of violence convulsing the country is overwhelmingly caused by the Taliban and allied groups like the Haqqani network.