WASHINGTON — The Obama administration is engaged in a debate about the extent of the president’s powers to use lethal force against terrorist organizations, and the deliberations have been accelerated by Al Qaeda’s recent decision to sever ties with a violent Islamist group in Syria.
The focus of discussions is whether a law giving the president authority to attack Al Qaeda affiliates still applies to the Islamic State of Iraq and Syria, the group disavowed last week.
Current and former US intelligence officials said that last week’s expulsion marked the first time Al Qaeda ejected a group that had formally joined its fold, a potentially risky move at a time when the terrorist network’s affiliates have largely eclipsed its core group in strength and relevance.
According to administration lawyers and intelligence officials, the expulsion removes the group from the short list of Al Qaeda associates that the president has virtually unlimited powers to attack under a law passed days after the Sept. 11, 2001, terrorist attacks. The group has emerged over the past year as a ruthless player in the Syrian civil war and one whose ability to project its power — and recruits — beyond the immediate battlefield is worrying Western intelligence agencies. On Monday, more than 20 recruits were killed when a bomb exploded during a class on suicide bombings, Iraq said.
The unofficial list of Al Qaeda affiliates is now down to four: the powerful offshoots in Yemen and North Africa, Somalia-based al-Shabab, and Jabhat al-Nusra, a rival of the Islamic State of Iraq and Syria within the Syrian opposition to President Bashar Assad.
Others think the Islamic State of Iraq and Syria can still be targeted because of its long-standing Al Qaeda ties and parallel ambitions. Officials who spoke about intelligence matters on the condition of anonymity emphasized that the administration has not made a ruling on the subject.
What appears at first glance to be a legal debate over an arcane dispute among terrorists is largely theoretical, since the administration has no current intention of attacking in Syria or Iraq. But the answer has implications for a far more important issue — what to do about the post-Sept. 11 law authorizing force as the Afghanistan war winds down and an increasingly decentralized Al Qaeda becomes more of an ideology than organized hierarchy.
In recent years, as new groups have posed threats to the United States and to its overseas personnel, the administration has adopted an increasingly elastic definition of the 2001 Authorization for the Use of Military Force to include groups it says are associated with the Qaeda and Taliban organizations covered by the law.
In a major national security speech in May, however, President Obama said the time had come to ‘‘recognize that the threat has shifted and evolved from the one that came to our shores on 9/11.’’ He said he wants to refine and ultimately repeal the Authorization for the Use of Military Force and would work with Congress to come up with an alternative better suited to current reality.
‘‘The default position is to do nothing,’’ said Representative Adam Schiff, Democrat of California and a member of the House Intelligence Committee who last year introduced legislation to sunset the law.
Continuing to rely on the Authorization for the Use of Military Force as the legal justification for counterterrorism operations ‘‘becomes increasingly strained when you’re not using it in the theater of war.’’