As if anyone seriously worries about the US bombing the Syrians. You do realize that using poison gas against civilians is considered a heinous war crime. Though if you want an analogy, if the US enters the Syrian War on one side it could tilt the war in that side’s favor (presumably the Kurds and/or the Syrian insurgents, to the detriments of ISIS and the Syrians (backed by the Iranians and Russians). However there is minimal chance of this leading to something bigger (since as it is the Russians are not in a position to do much, and the Iranians don’t want to totally alienate the rest of the Islamic world by supporting Assad after he goes around gassing people).
It does seriously hurt the Democratic party in the USA which invested much political capital in arguing that Trump is a Russian agent. It also might warn both Russia and North Korea that the “mad man” in the White House isn’t to trusted to turn a blind eye to their aggression (unlike his super-cool risk-averting predecessor).