Just yesterday Obama unequivocally declared it was Assad who was responsible.

WASHINGTON (AP) — The intelligence linking Syrian President Bashar Assad or his inner circle to an alleged chemical weapons attack is no “slam dunk,” with questions remaining about who actually controls some of Syria’s chemical weapons stores and doubts about whether Assad himself ordered the strike, U.S. intelligence officials say.

President Barack Obama declared unequivocally Wednesday that the Syrian government was responsible, while laying the groundwork for an expected U.S. military strike.

“We have concluded that the Syrian government in fact carried these out,” Obama said in an interview with “NewsHour” on PBS. “And if that’s so, then there need to be international consequences.” [...]

An intercept of Syrian military officials discussing the strike was among low-level staff, with no direct evidence tying the attack back to an Assad insider or even a senior Syrian commander, the officials said.

So while Secretary of State John Kerry said Monday that links between the attack and the Assad government are “undeniable,” U.S. intelligence officials are not so certain that the suspected chemical attack was carried out on Assad’s orders, or even completely sure it was carried out by government forces, the officials said. [...]

Another possibility that officials would hope to rule out: that stocks had fallen out of the government’s control and were deployed by rebels in a callous and calculated attempt to draw the West into the war.