Hundreds of thousands of people (500,000) have been killed and millions more displaced from om Syria. Europe is being overwhelmed by refugees from the region as well as from Pakistan and Afghanistan. They are also headed to the US in large numbers. The repercussions will be generational as the demography of Europe and the US change rapidly.
The Russians are establishing a foothold in the region once again after it took us almost 40 years to displace them in the ME.
This is largely a symbolic attack as a new President lays down a marker. The use of cruise missiles was meant to minimize any US casualties and the Russians were warned about the impending attack to prevent personnel casualties.
My concern is that this is just a one-time event similar to Clinton's attack on an aspirin factory. Is this just a sop to domestic opinion? Or is it the beginning of a strategy to stop the war in Syria and eliminate ISIS. And we don't want to remove Assad and wind up with someone far worse. Our experience in Libya, Iraq, and Iran should be evidence enough that creating a vacuum of leadership in these countries results in something far worse.
One small factoid you forgot. SYRIA IS A SOVEREIGN NATION.