N.Y. TIMES
Facing faltering support in foreign capitals and Congress for a strike against Syria, the Obama administration on Friday made an aggressive and coordinated push to justify a military intervention on the grounds that American credibility was at stake. President Obama and his top aides gave every indication that they were in final preparations for an attack that could pull the United States into a grinding civil war that has already claimed more than 100,000 lives.
Privately some American officials acknowledged mistakes over the past week in their buildup for a strike, not least misjudging the toxic politics of taking military action in the Middle East....it was not until Friday afternoon that the White House released what it said was evidence of chemical weapons use by the Assad forces — nearly 24 hours after Parliament had voted rather than beforehand, when it might have been used to build a coalition against Mr. Assad.
Deprived of the support of Britain, America’s most stalwart wartime ally, the Obama administration scrambled behind the scenes to build international support elsewhere for a strike that might begin as early as this weekend.
The White House got a boost on Friday from an ally that has had a long, tortured diplomatic relationship with the United States, and that vehemently opposed the American-led war in Iraq. In France, President François Hollande offered vigorous support for military action in Syria, saying that the Aug. 21 attack “must not go unpunished.”
Late on Friday, the Russian government condemned the threats of military action and said any strike not authorized by the United Nations Security Council would be a violation of international law.... Mr. Kerry said the United Nations could not respond to the Syrian chemical weapons attack because of Russia’s veto authority on the Security Council, which prevents the Council from galvanizing “the world to act, as it should.”
Mr. Obama insisted that he still had not made a decision about what action the United States would take in Syria, but he did say he was considering a “limited, narrow act.” He ruled out any operation involving American ground troops.
...Mr. Obama acknowledged the deep skepticism in the country — reflected in Congressional support that is tepid at best in both parties — about the necessity of a military strike. 
The decision about whether to use force, Mr. Kerry said, was a test of American standing in a world in which other nations might be tempted to pursue or use weapons of mass destruction.
Iran was first on the list of nations, Mr. Kerry said, and might take mistaken lessons from the chemical attack in Syria if the United States failed to respond.
“This matters also beyond the limits of Syria’s borders,” Mr. Kerry said. “It is about whether Iran, which itself has been a victim of chemical weapons attacks, will now feel emboldened in the absence of action to obtain nuclear weapons.”
A four-page intelligence summary said that American spy agencies had determined that 1,429 people had been killed in the Aug. 21 attack, carried out in the dead of night in rebel-controlled areas of the Damascus suburbs. Of that number, the report said, at least 426 were children.
The report contained little specific information about the electronic intercepts, satellite images and reports from spies that led intelligence agencies to conclude not only that the attack involved chemical weapons, but that they had “high confidence” the attack had been ordered by senior officials in President Assad’s government. “High confidence,” according to the report, is the “strongest position that the U.S. Intelligence Community can take short of confirmation.”
The report said that in the three days before the attack, American intelligence agencies began picking up indications that Syrian troops were preparing to use chemical weapons. Just before the attack was launched, according to the report, the troops put on gas masks. It is not clear from the report whether the United States or its allies made efforts to warn rebel groups in the Damascus suburbs.
American officials have said there is no information tying Mr. Assad directly to the attack, but the intelligence report said there was a “body of information” leading spy agencies to conclude “regime officials were witting of and directed the attack on Aug. 21.”
In one intercepted communication, according to the report, a “senior official intimately familiar with the offensive” confirmed that chemical weapons were used by Syria last week and was concerned that United Nations weapons inspectors might obtain evidence of the attack.