"I also fear for Syria's Christians if and when the regime falls."
You cannot stand by and watch thousands being slaughtered because you might not like what will replace the regime doing the slaughtering.
The Syrian people feel they have been abandoned, and they have.
By doing nothing we push Syria into the arms of the fundamentalists.
The alternative is that things will go on as they have been in Syria for decades, when the Assad family tortured, murdered and imprisoned and the world said nothing.
http://www.fco.gov.uk/en/travel-and-living-abroad/travel-advice-by-country/country-profile/middle-east-north-africa/syria/?profile=tradeInvestment
Jim Carroll