Obama shifts on Syrian rebels, but is it too late?

Obama himself was the chief mover behind the shift in US policy, said Syria analysts and US officials, who spoke on condition of anonymity.

"It seems to me that he has actually changed his mind. All the indications are that he was the main constraint on a more robust Syria policy all along," Andrew Tabler, of the Washington Institute for Near East Policy, said of Obama.

Deciding to expand the American support underscores Obama's lack of good options in Syria, more than three years into a civil war that has killed nearly 200,000 people.

The White House has to find a way to destroy Islamic State without allying itself with Syrian President Bashar al Assad, whom Obama called on to leave power more than three years ago. Assad's forces are also battling the group.

TOO LATE, OR STILL TIME?

Former congresswoman Jane Harman, who was among a group of national security experts who dined with Obama at the White House on Monday, said the president still believes he made the right decision two years ago, rejecting a proposal by top advisers to arm Syrian rebels.

"I think he thinks the world has evolved. The big change is ISIL," Harman said in a phone interview, using an alternate acronym for the group.

She said the role Obama sees for the moderate opposition is to hold ground now occupied by Islamic State, once it is forced out by the international coalition the president is assembling.

It is unclear whether more American weapons and training can shift the battlefield balance toward the US-backed rebels, who are badly outgunned by Islamic State, other militant groups and Assad's forces.

US officials describe the rebels as little match for groups such as Islamic State and its jihadist rival, the al Qaida-affiliated Nusrah Front.

Obama has acknowledged this but suggested they could become effective proxies on the ground if they were backed by American military power and received stronger support and training.

THIRD TIME LUCKY?

The Obama administration has announced backing for Syrian rebels twice before - with only modest results.

In June 2013, after Washington said it had evidence Assad had used chemical weapons, White House adviser Ben Rhodes announced the United States would expand assistance.

That program, overseen by the CIA, was delayed by opponents in the U.S. Congress. It has seen hundreds of rebels trained, but the United States has refused to provide the most advanced arms, such as surface-to-air missiles, for fear they would fall into the hands of anti-Western groups including Islamic State.

Then, on June 26 of this year, Obama proposed a USD 500 million package of assistance. Congress is still at odds over whether to approve the funds, and lawmakers say the White House has yet to present a specific plan on how the money would be spent.

As recently as Aug. 8, in an interview with the New York Times, Obama dismissed as "a fantasy" the argument that arming Syrian rebels earlier would have made a difference in the battle against Assad, who is backed by Iran and Russia.

The president's critics say he has warped their argument, which was not that the rebels would have achieved all-out victory, but that both Assad and Islamic State would be weaker.

"The case is compelling that had we taken a different course two years ago we’d be in a much better situation right now than what we face," said Frederic Hof, who served Obama as a special adviser on Syria and is now at the Washington-based Atlantic Council.