"Make no mistake whatsoever, the president's red line is real, the president said it would be a game changer," Secretary of State John Kerry told reporters in Guatemala on Wednesday, adding that France was sending its chemical weapons evidence to the U.S. for review. "The president has a whole set of options on the table and all of them are alive."
At the White House, press secretary Jay Carney cautioned that the U.S. still needed to see evidence that "makes a concrete case for the assertion that chemical weapons have been used, that can demonstrate when and by whom they were used and the consequences of that use."
For the United States, the stakes are high. Since Obama declared last summer that Assad's use of chemical weapons or transfer to extremist groups such as Hezbollah would constitute a "red line" that would have "extraordinary consequences," the United States has left open the possibility of all actions short of American military boots on the ground. Even as more than 70,000 people have been killed and Assad's forces have made significant gains against the rebels, the administration has played down threats of any armed action as long as Syria's vast chemical weapons stockpiles remained stowed away.
Swedish chemical weapons expert Ake Sellstrom, who heads the U.N. investigation team appointed by Secretary-General Ban Ki-moon, also has questions about the evidence he received Tuesday from the French government.
"Sellström cautions that the validity of the information is not ensured in the absence of convincing evidence of the chain-of-custody of the data collected," U.N. spokesman Martin Nesirky said.
Sellstrom and the secretary-general again urged Syria to allow the U.N. team into the country, stressing that "on-site activities are essential if the United Nations is to be able to establish the facts," Nesirky said.
Firming up evidence of such weapons use is thus paramount, especially after the U.S. spent more than $800 billion and lost almost 5,000 soldiers in an Iraq war justified on exaggerated claims about Saddam Hussein's nuclear ambitions and weapons of mass destruction programs. It is also a question of principle for Obama, who became commander-in-chief vowing opposition to "dumb wars" but showed himself willing to join with U.S. allies and partners in a limited mission in 2011 to overthrow Libyan dictator Moammar Gadhafi.
"We have a history, of course, on issues like this in the United States, and we all remember what happened around Iraq," State Department spokeswoman Jen Psaki said. "We want to make sure what the facts are certain before we make a conclusion."
Several U.S. officials say the administration is being deliberately ambiguous about what it knows of chemical weapons use in Syria. They cite a variety of reasons: the weak appetite among Americans for another war in the Arab world, a lack of good military options against a Syrian army with far stronger air defenses than Gadhafi's, and lingering hopes a peace process might take hold between the Assad regime and the Syrian opposition.
Developments beyond Washington's control, however, are chipping away at the U.S. position. After the regime and rebels traded accusations of chemical weapons use in Aleppo and Damascus in March, the administration sought to avoid any rash judgment. It took the British and French going public with their initial assessments of regime attacks to prompt a U.S. acknowledgement of similar intelligence.
It's unclear if a similar process might occur now. On Tuesday, French Foreign Minister Laurent Fabius said he had confirmation of multiple uses of sarin and at least once definitively by the regime, while the British cited positive tests for the same nerve agent. Both findings, based on samples taken from Syria, came hours after a U.N. team said it had "reasonable grounds" to suspect small-scale use of toxic chemicals in at least four attacks in March and April.
"We had this information. We had to publish it," Fabius told French television on Wednesday.
British Foreign Secretary William Hague said on BBC radio that the evidence is "very strong."
Both called for a U.N. investigating team to be allowed into Syria to take further samples. Assad is unlikely to grant unfettered access.
U.S. officials say they, too, have evidence of chemical weapons attacks, but they note reservations about the "chain of custody" and questions about who used the agents, how much were used and under what circumstances. No one in the administration believes the opposition either has chemical stockpiles or the know-how to deploy them, but they say more work needs to be done before any case for clear violations can be publicly and compelling defended.
The biggest challenge concerns what to do if and when the U.S. states unequivocally that chemical weapons were used.
At NATO headquarters on Wednesday, Defense Secretary Chuck Hagel said he'd not seen the new French evidence and that in the talks "we didn't get into any additional war plans regarding Syria."
Obama called for Assad to step down almost two years ago to allow for a more democratic Syria to emerge. Since then, the U.S. has given the opposition more than $120 million in nonlethal aid but has taken no significant action to ensure Assad's departure. Others such as Kerry have spoken of increased support to the rebels to convince Assad he can't win the war. Yet as American officials debate the merits of sending weapons, the Assad regime has succeeded in regaining more territory through a military counteroffensive backed by allied Iranian and Hezbollah forces.
If the U.S. announces that chemical weapons were used, and then doesn't offer any immediate consequences, it could suffer a damaging loss of credibility in a part of the world still rife with unstable states and where Obama has presented another "red line" to Iran, concerning its disputed nuclear program.
"For the Obama administration, Syria's chemical weapons usage is an operational policy matter, not just an analytical one," said Robert Danin, senior Mideast fellow at the Council on Foreign Relations. "Having said chemical weapons use by Syria would be a 'game changer,' the administration is now going to have to explain how the game has changed and how the U.S. is going to play in this game."
Patience is wearing thin, however, with the Syrian war showing no signs of abating.
The Syrian opposition, engaged in a contentious reform process at Washington's behest, may see continued U.S. inaction as evidence it will never get American military assistance in its fight against Assad, prompting rebels to abandon their vision of a democratic future and turn to the extremists who can guarantee deliveries of guns and ammunition. Proponents of intervention in Congress, led by lawmakers such as Sen. John McCain, R-Ariz., are growing in number. And America's allies in Europe and the Arab world are clamoring for U.S. leadership.
"We have brought forward elements of proof that now require the international community to act," French President Francois Hollande said Wednesday, without spelling out what his own country is willing to do. The United States, as the world's only superpower, may not have that luxury.
A U.S. national security shakeup announced Wednesday could drive Obama into a more forward-leaning posture. U.N. Ambassador Susan Rice, who supported military force in Libya two years ago, is replacing Tom Donilon as national security adviser. Samantha Power, a human rights advocate and former White House adviser who has championed intervention to prevent genocide and other atrocities, is coming in for Rice at the global body.
Still, the question of intervention ultimately rests with the commander-in-chief.
And Obama remains "very reticent to militarily enforce his August red line on chemical weapons," said Andrew Tabler, a Syria expert at the Washington Institute for Near East Policy. He said the president's position calls into question whether he meant to issue a red line at all, given that Assad's forces allegedly used chemical weapons several times and likely won't quit now.
"With Hezbollah and Iran helping the regime go on the offensive, do we really think Assad is going to stop using the full lethality of his arsenal?" he asked.