The embattled Assad regime escalated its horrific attempts to crush Syria’s opposition movement this week after Russia, one of its few allies, blocked action by the U.N. Security Council.

On Friday, Russian Prime Minister Vladimir Putin warned against any foreign intervention, saying that other countries should “not interfere under any circumstances.” This warning came after Russian Foreign Minister Sergei Lavrov met with Syrian President Bashar al-Assad on February 7 and afterward said that his message to Assad about the need to end the violence “has been heard.”

But Assad has apparently interpreted the vetoes cast against U.N. action by Russia and China as a green light to ramp up attacks on Syria’s burgeoning opposition movement. The Assad regime stepped up its offensive in the city of Homs, a resistance stronghold, invading the city with tanks and bombarding it with rockets and artillery. Syrian opposition forces claimed that the regime is stockpiling chemical weapons and issuing gas masks to soldiers in Homs.

Russia has strong ties to the Assad regime, its last important Arab ally after the downfall of Iraq’s Saddam Hussein and Libya’s Muammar Qadhafi. Moscow is assertively protecting its strategic investment in that regime. Syria has granted Russia a naval base at Tartus. It has also bought $4 billion in Russian arms in recent years, and Moscow wants to collect on that debt, which it fears would be written off by a new regime. Moscow also wants to protect about $20 billion in economic investments tied to the regime that have been made by Russia’s powerful energy conglomerates.

The Assad regime has also been aided by Iran, which has dispatched members of the elite Quds Force of the Islamic Revolutionary Guard Corps to assist Assad in repressing his own people. Iran has much to lose if its most important ally is overthrown.

The Obama Administration, which has consistently been behind the curve in reacting to Syrian events, closed the U.S. embassy in Damascus on Monday due to the deteriorating security situation. The Administration has ruled out a military intervention but has escalated sanctions against the Syrian regime.

The Obama Administration appears willing to do little that is not explicitly endorsed by the U.N. Security Council. But thanks to the Russian and Chinese veto power, this is a prescription for endless frustration. Meanwhile, the Assad regime, backed by its friends in Moscow and Tehran, continues to massacre the opposition.