(CBS News) President Obama is weighing the diplomatic and political implications of intervention in Syrian -- his decision tosurprised many on Capitol Hill over the weekend.
On Friday, Obama said the administration would "consider options that meet the narrow concern around chemical weapons" and said he would consult -- but not wait for approval -- from Congress. But later Friday, the president convened an oval office meeting with his chief advisers to inform them he would seek Congressional approval for any attack.
Saturday in the Rose garden, Obama explained the decision: "I'm ready to act in the face of this outrage. Today, I'm asking Congress to send a message to the world that we are ready to move forward together as one nation."
"Before he made the decision to go to Congress he recognized that he was pretty much alone. The British have decided to opt out and they're going to stay out. There is no chance of getting a resolution through the U.N. security council and so without Congressional approval, the president would be in a position of truly acting alone," Sanger said on "CBS This Morning."
The decision was likely motivated by two factors, according to Sanger: the need for political cover and to involve White House naysayers in Congress in a move that could be criticized should the situation on the ground in Syria deteriorate or the Assad regime gain in strength due to or following a U.S. military strike.
President Obama is looking to "take many in Congress -- including many who have been critical of him -- and put them in the same box he's in, which is to decide first whether to take military action but secondly how limited that should be," Sanger said. "One of the risks is you take some kind of symbolic action and then in the end Assad survives it and then ends up looking stronger.
"If there's are limits to be placed on American military action, I think the president wants the Congress to be part of that as well," Sanger said.
The weekend policy shift was not a change based on new evidence -- the evidence indicating the use of chemical weapons by the Assad regime remains strong -- it was a change motivated by politics, Sanger said, adding "the president didn't want to be as isolated [and] he had heard many in Congress say, 'How come we're not being consulted?'"
In terms of the potential fallout following a vote on intervention, Obama risks looking "even more isolated than he was before" if he does not get authorization from Congress. And, Sanger said if Congress turns the president down, "it will make it look like the United States is pulling back from the world at a time when many in the Middle East believe we are anyway."
"There are many abroad who are wondering whether the president has gotten weak-knee'ed here," Sanger said. "For the Israelis, the Saudis, for others who are concerned about the president's willingness to say, confront Iran, if the nuclear situation turns worse, they are looking at this with considerable nervousness."