NEW YORK // With America's "war on terror" now focused far beyond its original targets in Afghanistan and Pakistan, the legal justifications for it have become increasingly irrelevant and untenable, even to those waging it.
The Pentagon's top lawyer, Jeh Johnson, is the first Obama administration official to raise publicly the challenge of overhauling the vast legal framework - much of it still secret - that was created in the wake of the September 11, 2001, attacks on the United States.
Mr Johnson, who is stepping down as the US defence department's top lawyer at the end of the year, told an audience at the Oxford Union: When the organisation responsible for the 9/11 attacks has been destroyed, "we must be able to say to ourselves that our efforts should no longer be considered an 'armed conflict' against Al Qaeda and its associated forces; rather, a counterterrorism effort against individuals who are the scattered remnants of Al Qaeda, or are parts of groups unaffiliated with Al Qaeda, for which the law enforcement and intelligence resources of our government are principally responsible".
The speech was the first public acknowledgement that the laws used to justify US actions after 9/11 no longer reflect the reality on the ground and the actions of the armed forces fighting alleged terror groups.
Few analysts believe that targeted assassinations, indefinite detention and other controversial practices by Washington will end any time soon, as the threat of Islamist militants metastasises in the wake of the Arab Spring.
The speech "certainly contradicts the way the Obama administration is actually preparing to confront this threat, which it seems to believe will be ongoing for some time", said Daveed Gartenstein-Ross, an attorney and terrorism expert at the Foundation for the Defence of Democracies, a think tank based in Washington.
Still, more than a decade after the events in New York and Washington, it is time to reassess what "war" against purported terror groups means. It will not be easy, said Wells C Bennett, a national security legal expert at the Brookings Institution in Washington.
"It will be difficult for policymakers because they're going to have to be thinking about a terrorism threat that may no longer constitute an armed conflict [definable as war], but will still be very serious," he said.
Mr Johnson said in his speech that there will be a "tipping point" when Al Qaeda leadership has been rendered unable to "attempt or launch a strategic attack on the United States". "[N]ow that efforts by the US military against Al Qaeda are in their 12th year, we must also ask ourselves: how will this conflict end? It is an unconventional conflict, against an unconventional enemy, and will not end in conventional terms."
The retreat to a pre-September 11 criminal-law framework will not work in a world where weak states cannot enforce their writ and violent, non-state groups become more powerful, Mr Gartenstein-Ross said. "On the other hand, is the current [framework] good? No. And I don't think we're having an honest conversation about it."
Opposition to the US military prison at Guantanamo Bay in Cuba has made the issue of detention politically toxic, which has reinforced in some measure the Obama administration's preference for assassination, such as the drone strikes against militants in northwestern Pakistan and in Yemen, said Mr Gartenstein-Ross.
While the core leadership of Al Qaeda in Afghanistan and Pakistan has been degraded by drone strikes, the post-Arab Spring in the Middle East has created new opportunities for Islamist militants. These Al Qaeda "fellow travellers", analysts say, will pose a serious threat to US interests in the Middle East, though rarely to the country itself.
The new opportunities that Islamist militants have found in the post-Arab Spring vary by country, but there are features common to all. In Yemen, for example, militants stepped in to provide electricity and medical supplies when the provision of government services broke down in the year-long uprising, said Will McCants, a former counter-terrorism adviser to the State Department.
"It's just a big, messy stew of all these factors coming together for the primary reason that these states are either collapsing or they're weak and the new regimes are not quite sure of themselves yet," he added.
The opportunity for militant groups to provide limited forms of governance in a chaotic political situation has put them in a strong position to focus on local grievances, rather than targeting the US, said Mr Gartenstein-Ross. "Part of it is opportunity and part of it is refining the way they approach the world," he added.
If the US felt threatened by any of these groups, the embedded position of the militants in local society could make them more difficult to combat, the analysts said. The US must also carefully consider how any response may destabilise fragile new democratic regimes.
Some militants have already begun to alienate themselves. The Nusrah Front in Syria, one of the largest anti-regime groups, has links to Iraq's Al Qaeda affiliate and carried out a series of bloody suicide attacks in Damascus that killed scores of civilians. They have, however, learnt their lesson and "it is generally acknowledged among jihadis that this is a bad move for their cause", Mr McCants said.
The US will reportedly designate the Nusrah Front as a foreign terrorist organisation this week, even though it has been one of the most brutally effective insurgent groups in the uprising against president Bashar Al Assad's regime.
While analysts disagree over how much control Al Qaeda has over its allies and sympathisers spread across the region, there is little doubt that the group's followers still subscribe directly to Al Qaeda's ideology and, if the opportunity arises, will try to strike at US interests.
"The battle is not over," said Mr Gartenstein-Ross.