Secretary of State Kerry just gave a press statement which he started 26 minutes late. I will spare you my rough notes and point to the Washington Post transcript.
Obama will go to Congress and the American people to make the case against Syria.
The unclassified intelligence assessment is here (pdf) There is also a unspecific map of the allegedly targeted areas.
Kerry cited intelligence that sounded weak to me. He claimed 1429 killed by "chemical weapons" in the recent incident. That doesn't make sense. The 30+ videos I have seen of the incident have shown about a 100 dead people max.
Then came some heart bleeding nonsense, the usual USA, USA, USA and the false claim that "the world stands with us".
He then promised some U.S. reaction but mentioned no legal base for that.
I'll take some time to read the assessment and will later let you known my opinion on it.
Update: Read through the very short unclassified assessment and it basically says "we know" and "trust us". Not one bit of something concrete or independently verifiable. Some circumstantial observations in a battlefield that may mean this or that. This sentence especially makes we very suspicious:
We have identified one hundred videos attributed to the attack, many of which show large numbers of bodies exhibiting physical signs consistent with, but not unique to, nerve agent exposure.
The issue here is that exposure to a nerve agent like Sarin should show certain symptoms that the people in the videos do NOT show. Sarin "closes the pupils and opens the anus". In those videos all people seem clean, none have defecated, none have thrown up. That is inconsistent with chemical weapon effects and not mentioned in the assessment.