Obama “needs to be thinking about . . . how quickly we are going to get out of Afghanistan. He’s probably going to do it more quickly than people think but not as quickly as we need,” Armitage said.

Obama’s Afghanistan strategy faces other potential pitfalls.

His approach has been built around a 33,000-strong troop surge into the Taliban’s southern heartland that ended in September and an effort to start peace talks between insurgent leaders and President Hamid Karzai’s government.

The surge hurt the Taliban but failed to extinguish the insurgency, while the peace talks initiative appears to have all but collapsed. Meanwhile, the unpopular Karzai is to leave office after April 2014 presidential elections, corruption remains endemic and a reduction in foreign funds threatens to drive the desperately poor country deeper into poverty.

As a result, there is a real danger that Afghanistan could collapse into all-out civil war even as the U.S.-led international force departs.

Obama’s strategy also will hinge on relations with nuclear-armed Pakistan, whose cooperation is critical to the U.S. pullout. Yet Islamabad, which officially is a U.S. ally, has different strategic goals in Afghanistan, including preventing rival India from gaining influence in Kabul.

U.S.-Pakistan ties are recovering from a series of mishaps and a U.S. refusal to halt pilotless drone attacks on terrorist targets inside Pakistan that drove relations to their iciest level since the founding of Pakistan in 1947. But relations remain cool, encumbered by serious differences, and it remains unclear how Obama will address them.

Iran

Perhaps no foreign policy issue will demand more of Obama’s attention and energy – and almost immediately – than the crisis over Iran’s nuclear program, which threatens to ignite a conflict that could send petroleum prices soaring, driving the world economy into a tailspin and derailing the fragile U.S. recovery.

Intense U.S., European and U.N. sanctions are hurting Iran’s oil-dependent economy. But the Islamic republic persists in defying demands that it stop enriching uranium, which it says is for civilian uses and Western powers and Israel charge is part of a covert nuclear weapons program.

Despite deadlocked negotiations, both the Obama administration and Iran appear eager to restart multilateral talks, which could resume later this month. Obama has resisted pressure from Israeli Prime Minister Benjamin Netanyahu to launch military strikes at Iranian nuclear facilities, saying there is more time to reach a political resolution before Iran acquires enough low-enriched uranium to transform into fuel for a warhead.

Some experts see the outline of a deal: Iran would halt its enrichment of uranium to 20 percent, ship its existing stocks abroad and shutter its deeply buried Fordow production facility in return for an irreversible lifting of sanctions after each step.

“I think the problem is one of sequencing,” said Alireza Nader of the RAND Corp., a research institute. “We have to see now if Iran will be willing to take certain steps to build international confidence. Is there potential for it? Yes, because the regime is facing a lot of pressure.”

It would take action, however, by a pro-Israel Congress to permanently lift U.S. sanctions, restricting Obama’s deal-making ability. And Iran’s regime is divided between factions jostling for power in the run-up to presidential elections next year.