It would be quite lengthy if I detailed everything, but in summation, we lack any concrete evidence that the attack was carried out by Assad's regime, so I'm against any action at this time. However, I am in favor of an international solution if concrete evidence is ever produced. In general, I'm not on the "America should be the world police" bandwagon, but I'm equally dismayed by the pacifist arguments that say war, for any reason, is immoral or wrong. With that being said, there are a lot of intricacies and complexities when it comes to most conflicts, so each has to be weighed and judged on its own merit. I think a lot of people get caught in these ideologies where America either seems to "always be right" or "always be wrong." Because of that, people are either naive about other governments or our own. The reality, though, is somewhere between the extreme perceptions of America as "saviors of humanity" and an "evil plague on Earth."
One other thing that is obvious but worth mentioning is the fact that as citizens, we lack a lot of information (from our country and others) that some politicians, military personnel, and certainly the president (or equivalent leader) have when it comes to things like this. In other words, citizen opinions are, by default, opinions confined by limited information. I don't see anything wrong with a certain lack of transparency, as I think secrecy is necessary in some instances. However, that doesn't mean one should blindly trust what the government says. Independent research, logic, and critical thinking skills should always be applied when trying to form opinions on important topics.