I blame the UN for being a dictatorship of Russia, China, France, America and the UK, based on outdated ancient legislation based on the outcome of WW2. An organization that supposedly represents all the nations on the world and does so to further peace and prosperity should NOT be rules by 5 states who can decide whenever they want to veto military action against dictators. Either everyone has a right to veto, or nobody has a right to veto.
See Israel as a prime subject for Abuse of veto by America. In Syria however the case is slightly different as of course the Russian and Chinese dictatorships are scared that one day they to might be toppled if they continue to support these rebellions against dictatorships. So yes China and Russia veto to safe their own hides, America does it because Assad is their buddy, much like Mubarak and many other dictators who help them keep the status quo.