The US do not care much about the UN (inspectors)

“http://www.independent.co.uk/news/world/middle-east/syria-crisis-as-us-prepares-to-reveal-intelligence-on-suspected-damascus-chemical-weapons-attack-what-do-we-know-already-8787788.html”

“Officials in the US and the UK have made it clear that any decision to proceed with military action will be based on intelligence gathered by the US, and not the findings brought back by the UN inspectors currently on the ground in Syria.”