Suggestion: the US has no more obligation to fight Assad in Syria than it has to fight the rulers of Saudi Arabia, Bahrain, Egypt, etc.

When Assad faced a campaign of peaceful protests for human rights, that campaign merited support on ethical grounds. Today's situation is totally different.

When a violent uprising started in parallel with that campaign, Assad said it was started by Islamists, and that may have been true. Once the fighting started, various Sunni groups, reportedly less fanatical, joined in; but they have been eclipsed by the jihadi groups funded by Saudi Arabia and Qatar.

That the US does not have to fight all these dictators does not mean it must or should give them strong support, as it does now.

The reasons the US government has stated for supporting so many Arab dictators and monarchs are: to oppose the Soviet Union (obsolete), and to promote stability. Ironically, this practice has had the effect, across decades, of enabling Islamist fanatics to win the support of those who oppose the dictators and monarchs for other reasons.