I've yet to be convinced that the casualties shown on TV were caused by a chemical attack. There could be a number of reasons why they suffered that don't necessarily require a chemical weapon attack. The destruction of a chemical plant, warehouse with chemicals, electronics factory, etc, could all account for the symptoms seen. The only other evidence is of government planes dropping bombs producing a 'firey smoke' and some intercepted communications by the US. We should let the inspectors get on with the job that they've been given.
Nor am I convinced that we have the military means to carry out an effective response, we could target air-defense sites, HQs, depots and airfields, but there would inevitably be civilian casualties. It's a bit pointless to kill more civvies that you might protect be doing nothing. It's not as if we, or even the US, could intervene on the ground in Syria. The UN Security Council will be effectively neutered because of the Russian veto. If there really is evidence that the Assad regime was responsible for a CBRN attack then the best thing would be to seize Syrian government assets, indite him and the rest that are implicated as war criminals, and supply medical and food aid to the refugees and insurgents. It will help to bleed Assad of funds and resources. Beyond that our responses are severely limited.
Syria is NOT the same as Iraq or Afghanistan, it is far more like a western country in terms of infrastructure, industry, education and social values. Iraq had been bled by years of conflict of Iran and been cut-off by the US. Much of Afghanistan is barely beyond a neolithic lifestyle, subsistance farmers struggling just to get by. Both countries had be strained by the maniacs in charge to a much greater degree than the Assad regime.