Syrian Slaughter - No Intervention?

The Syrians are shelling one of their own cities - killing hundreds, wounding thousands.  But President Obama says this conflict should be resolved WITHOUT outside military intervention?  What makes this war different than the one in Libya?  I'm confused.

Plus, the U.S. evacuated all its diplomats from the country as Syrian forces intensified a shelling assault on the restive city of Homs.   The offensive began Saturday, the same day Syria's allies in Russia and China vetoed a Western- and Arab-backed resolution aimed at trying to end the brutal crackdown on dissent.

I guess we know where China and Russia stand - with their Iranian and Syrian allies, that's where.