LONDON - The war on terror is not an endless conflict and the U.S. is approaching a "tipping point" after which the military fight against al-Qaida will be replaced by a law enforcement and intelligence operation, the Pentagon's top lawyer has said.
Jeh Johnson told an audience at Oxford University that the core of al-Qaida is "degraded, disorganized and on the run," according to a transcript of Friday's speech.
Johnson, general counsel to the U.S. Defense Department, said that once most al-Qaida members are captured or killed, armed conflict would be replaced by "a counterterrorism effort against individuals" led by law enforcement and intelligence agencies.
His speech to the Oxford Union debating society marked rare public comments by a senior U.S. official about the end of the armed conflict launched after the Sept. 11 attacks.
Shortly after 9/11, U.S. legislators passed a law that essentially granted the White House open-ended authority for armed action against al-Qaida.
Despite a promise to close the Guantanamo Bay prison camp for terror suspects, President Barack Obama has largely carried forward the anti-terrorism policies of his predecessor, George W. Bush. He authorized the raid that killed al-Qaida leader Osama bin Laden and has expanded the use of unmanned drone strikes against targets in Pakistan and Yemen.
Johnson insisted U.S. actions were "firmly rooted in conventional legal principles," but elements of the secrecy-shrouded conflict are highly controversial - particularly the use of drone strikes, which U.S. authorities do not publicly acknowledge.
U.S. officials have used the example of World War II to rebuff critics of its assassination of al-Qaida leaders, including bin Laden and radical preacher Anwar al-Awlaki, an American citizen killed in a drone strike in Yemen in 2011.
Johnson said the United States relied on the law of war and on principles of "proportionality, necessity and distinction" in its use of lethal force.
But he said the war would one day end. Although there was no question of a compromise or peace treaty with al-Qaida, neither could the U.S. "capture or kill every last terrorist who claims an affiliation with al-Qaida."
He said the time would come when "there will come a tipping point ... at which so many of the leaders and operatives of al-Qaida and its affiliates have been killed or captured, and the group is no longer able to attempt or launch a strategic attack against the United States."
He said the end of the war on terror would present legal challenges, because the U.S. would no longer be able to rely on the law of war as legal grounding.
Any remaining Guantanamo Bay detainees would have to be dealt with according to "conventional legal principles" - which appear to suggest that if they have not been charged or convicted, they must be released.
"War must be regarded as a finite, extraordinary and unnatural state of affairs," Johnson said. "In its 12th year, we must not accept the current conflict, and all that it entails, as the `new normal.'"