Instead of the USual reactionary violent, military missiles and war, US could wait for the UN findings and support prosecution by the International Criminal Court.
US could enforce existing sanctions and impose stricter ones like prosecuting banks that surreptitiously do business with the Assad regime.
US could explain their own indiscretions and war crimes and try diplomacy with rivals like Russia and China, and by ending our military aid to inhumane regimes much like Syria, US could then ask Russia to stop selling weapons to Assad without upsetting the balance of power any further in the US direction.
If US bombs Syria, it will destabilize the Middle East even further. If US misses its target innocent civilians will suffer and die, and even if US destroys some of Assad’s arsenals he can just buy more and take the money to buy them from the people, just like the US does. And Assad will probably retaliate, leading to the escalation of violence.
Links to details of the above can be found at https://twitter.com/polysensory along with other news mainstream media fails to report.
Also see “War is not a Panacea” page below for a ‘philosophical’ study of the militarization of the US.