The Obama administration's legal team is split over how much latitude the United States has to kill Islamist militants in Yemen and Somalia, a question that could define the limits of the war against al Qaeda and its allies, according to administration and Congressional officials.
The debate, according to officials familiar with the deliberations, centres on whether the US may take aim at only a handful of high-level leaders of militant groups who are personally linked to plots to attack the US or whether it may also attack the thousands of low-level foot soldiers focused on parochial concerns: controlling the essentially ungoverned lands near the Gulf of Aden, which separates the countries.
The dispute over limits on the use of lethal force in the region has divided the State Department and the Pentagon for months, although to date it remains a merely theoretical disagreement. Current administration policy is to attack only "high-value individuals" in the region, as it has tried to do about a dozen times.
But the unresolved question is whether the administration can escalate attacks if it wants to against rank-and-file members of al Qaeda in the Arabian Peninsula, based in Yemen, and the Somalia-based Shabab. The answer could lay the groundwork for a shift in the fight against terrorists as the original al Qaeda, operating out of Afghanistan and Pakistan, grows weaker.
One senior official played down the disagreement on Thursday, characterising it as a difference in policy emphasis, not legal views.
Defense department lawyers are trying to maintain maximum theoretical flexibility, while State Department lawyers are trying to reach out to European allies who think that there is no armed conflict, for legal purposes, outside of Afghanistan, and that the United States has a right to take action elsewhere only in self-defense, the official said.
But other officials insisted that the administration lawyers disagreed on the underlying legal authority of the US to carry out such strikes.
The fate of detainees at Guantánamo Bay, Cuba, also hangs heavily over the targeting debate, officials said.