For me, the Bush example urging him to stay out is more apposite than the Clinton example. In both Bosnia and Rwanda there was a pretty clear villain carrying out the genocide. That is less clear in Syria.
The first question is to be resolved is whether the Syrian government used chemical weapons. It’s pretty clear that chemical weapons were used, but it’s less clear who used them. Given Obama’s “red line” it would appear stupid for Assad to use chemical weapons; he would just be inviting the US to intervene. But maybe Assad is stupid, or maybe he is counting on that appearance of stupidity to discourage retaliation. On the other hand, the rebels have been pleading for the US to intervene against Assad. Because of Obama’s “red line,” the rebels have a strong motivation to make it look like Assad used chemical weapons, but do they have access to chemical weapons? It seems possible that they might, either brought from Syrian stockpiles by defectors to the rebels, or given to them by sympathizers in other countries. However, I know of no evidence that the rebels to have such weapons, except for some suspect photos circulated by the Syrian government.
If the Syrian government did use the chemicals, then what were the circumstances? Was it a top level government decision by Assad himself, someone lower but still senior, or were they used by a low level person without permission from the government. The New York Times said that the intelligence it knew of did not show a “smoking gun” linking Assad to the weapons’ use, although it did link someone in the government to their use. If the weapons were used by some low-level person, an American attack on Syria’s command and control network might actually increase the likelihood of CW use. Because of defections, I would be leery of communications intelligence; defectors might have Syrian government radios, for example. The intelligence would have to be good, in light of the disastrous intelligence presented to the UN to justify the US invasion of Iraq.
On balance, I think the US should stay out of the Syrian civil war at this time. Condemn the use of CW, but don’t intervene militarily.