How to prevent subsequent gas attacks aka war crimes in Syria?
Poison gas, biological weapons and nukes have achieved a special status as weapons that are radioactive (to use a bad pun). Their use is considered a serious war crime.
So, what action should be taken to prevent subsequent attacks? A limited American missile strike is unlikely to have much effect. So what would? There is no stomach anywhere for a full invasion like Iraq.
How can the perpetrators be punished? At the least arrest warrants for a war crimes trial should be made. But realpolitik considerations make that impossible: China and Russia will protect their friends in Syria. So does that mean gas attacks can proceed with impunity?
In the end, President Assad has the winning hand, because regardless of a US missile attack, he likely will be able to use gas again with few consequences.