Recent Russian intervention in Syria raises a quandary for the U.S. about what it can do to resolve the conflict and whether it should risk allowing Syrian President Bashar al-Assad to increase his tenuous hold on power.
Putin has been building up Russia's military presence in Syria to support Assad, and that earned him a warning from President Obama at the U.N. General Assembly that Assad cannot stay.
00:18 Russia and Syria pause in bombing of rebel-held sections of Aleppo
19:16 Analysis: Why are Russian warships in British waters?
22:36 Wary of Russian Guarantees, Residents Stay Put in War-Torn Aleppo
16:10 The Putin's 'Puppet' Accusations Speak Volumes About the Sad State of U.S.-Russia Relations3