WASHINGTON -- When President Barack Obama rebuffed four of his top national security officials who wanted to arm the rebels in Syria last fall, it put an end to a debate of several months over how aggressively Washington should respond to the strife there that has now left nearly 70,000 dead.
But the decision also left the White House with no clear strategy to resolve a crisis that has bedeviled it since a popular uprising erupted against President Bashar Assad almost two years ago. Despite a U.S. nonlethal assistance program to opponents of the Syrian government and $365 million in humanitarian aid, Mr. Obama appears to be running out of ways to speed Mr. Assad's exit.
With conditions continuing to deteriorate, officials said, the president could reopen the debate over providing arms to select resistance members in an effort to break the impasse in Syria. The question is whether a wary Mr. Obama, surrounded by a new national security team, would come to a different conclusion.
"This is not a closed decision," a senior administration official said. "As the situation evolves, as our confidence increases, we might revisit it."
Mr. Obama's decision not to provide arms when the proposal was broached before the November election, officials said, was driven by his reluctance to get drawn into a proxy war and his fear that the weapons would end up in unreliable hands, where they could be used against civilians or Israeli and U.S. interests.
But as the United States struggles to formulate a policy, Mr. Assad has given no sign that he is ready to yield power, and the Syrian resistance has been adamant that it will not negotiate a transition in which he has a role.
On Monday, European Union foreign ministers decided against easing an arms moratorium despite objections by Britain. In what appeared to be a compromise, the ministers agreed to "provide greater nonlethal support and technical assistance for the protection of civilians," according to the EU's website.
As the Syria conflict has unfolded, the State Department has funneled $50 million of nonlethal assistance to the Syrian opposition, including satellite phones, radios, broadcasting equipment, computers, survival equipment and related training. This support, officials say, has helped Syrians opposed to the Assad government communicate with one another and with the outside world, despite efforts by Syrian forces to target rebel communications, using equipment supplied by Iran.
But the State Department does not provide nonlethal assistance to armed rebel factions. This has greatly limited the influence the United States has with armed groups likely to control much of Syria if Mr. Assad is ousted.
Although the White House has focused on the risks of providing weapons, other nations have had no such reservations. Russia has continued to provide arms and financial support to the Assad government. Iran has supplied arms and paramilitary Quds Force advisers. Hezbollah has sent militants to help Assad forces. On the other side, antigovernment fighters affiliated with al-Qaida have been receiving financial aid and other support from Middle East backers.
The arming plan considered last year originated with then-CIA director David H. Petraeus and was supported by former Secretary of State Hillary Rodham Clinton. The goal was to create allies in Syria that the United States could work with during the conflict and after Mr. Assad's removal, if that occurred. Each had a reason for supporting it.
Mr. Petraeus had experience as a general in Iraq training Iraqi fighters and had long worried that militants traveling through Syria to join al-Qaida in Iraq might one day reverse course and challenge the Assad government. Ms. Clinton signed on to the initiative after frustration that the Russians had walked away from a transition plan she thought was agreed on in June.
Defense Secretary Leon E. Panetta supported the plan, which offered a way to influence the military situation inside Syria without involving U.S. forces. So did Gen. Martin E. Dempsey, chairman of the Joint Chiefs of Staff, calculating that it was important to bring the conflict to a close before the Syrian state collapsed, and there was nothing to hand over to Mr. Assad's successor.
But the president, who had campaigned on the theme that "the tide of war" was receding, was more skeptical, fearing such a move would, in effect, draw the United States into a proxy war against the Syrian government and its Iranian and Russian backers, with uncertain results.
His wariness was reinforced, officials said, by his closest advisers, including Vice President Joe Biden and national security adviser Thomas E. Donilon, both of whom advised against it. Also skeptical, officials said, was Susan E. Rice, the U.N. ambassador. Her opposition was noteworthy, given that she had pushed for military intervention in Libya.