It is said that generals are always fighting the last war. And the public also tends to draw lessons from the last event that seems comparable to our current situation. Everyone has indelibly etched on their minds the case of Iraq and its illusory weapons of mass destruction. The only reasonable positions left on that fiasco are to argue either that we never should have attacked Iraq in the first place, or that we should have handled the aftermath much differently. Given that disaster, what are we to do about Syria? How do we prove that we have learned something from history?
In this case, we may find that the evidence that Syria used chemical weapons against its own people is irrefutable. Just because we got it wrong about Iraq doesn't mean we are wrong about Syria. In fact, the intelligence community's experience with Iraq probably makes it more likely that we are right this time. In this case, we are also not in danger of provoking a civil war, for the simple reason that there has already been a civil war going on in Syria for the past two years. The plan is merely to exact punishment on the Syrian government for crossing a red line. Of course there are risks involved in taking action, but again, our experience in Iraq probably makes it more likely we will avoid becoming embroiled in a civil war in that country.
The simple fact is, as Humphrey Bogart explained at the end of The Maltese Falcon, that when somebody kills your partner, you're supposed to do something about it. It doesn't matter what you thought of the guy. That translates, in international law, to when somebody uses chemical weapons, you're also supposed to do something about it. It doesn't matter if you don't like the rebels much more than the government. The government of Syria has still crossed a line, and it would be bad business all around to let them get away with it. That doesn't mean we would be going to war against Syria if we initiate military action. We should be pursuing a peaceful resolution of that conflict as strongly as ever. What a military strike against Syria would instead represent is a penalty, of the kind that a referee inflicts in a game, when one team violates the rules.
And just because the British Parliament has already blocked that country's involvement in any military action against Syria does not absolve the US of responsibility to take some action. By drawing the wrong lessons from history, Britain is likely to look foolish twice. The British public wants to avoid the humiliation of following the US lead into an inadvisable war in Iraq. That might cause them to suffer a different kind of humiliation by shamefully standing by while another government commits a gross violation of human rights and international law. We need to evaluate this case on its own merits, and find a path to do what is right and necessary.