Syria’s downing of a Turkish fighter jet at last opens the door to the U.N. Security Council, which is charged with upholding international peace and security, to consider legitimate collective action against Damascus.

The flight of thousands of Syrian refugees into neighboring countries had already turned the Syrian conflict into a matter for the U.N., but Russia and China had blocked moves to impose sanctions, citing Syrian sovereignty.

However, Chapter VII of the U.N. charter provides for the 15-member Security Council to take measures, including the use of force, to “maintain or restore international peace and security.”

In the case of Libya, the Security Council used the fig leaf of the principle of Responsibility to Protect (R2P) to push through a tough resolution in March last year. That resolution opened the door to regime change by calling for “all necessary measures” to protect Libyan civilians. It’s clear from Russian and Chinese statements that those two governments, with veto power on the Security Council, would not contemplate such a resolution again. All they have agreed to so far is the U.N. observer mission, treated with contempt by President Bashar Assad.

The U.S. ambassador to the U.N., Susan Rice, has told the council that its inaction “represents a colossal failure” to protect Syrian civilians. She says it’s time to invoke Chapter VII. The downing of the jet belonging to a NATO member gives the U.N. Security Council the excuse and the necessity to do so. Prime Minister Recep Tayyip Erdogan has told parliament that Syria represents a “clear threat” to Turkey.

Binding draft U.N. sanctions being considered by the United States, United Kingdom and France would give the Syrian dictator pause for thought if the council can finally come together. It’s only when he can no longer hide behind his Russian and Chinese enablers that he will be forced to negotiate the endgame.