Reuters reports: President Vladimir Putin offered a glimpse of international compromise over Syria on Wednesday, declining to entirely rule out Russian backing for military action as he prepared to host a summit of world leaders.

As the United States and allies prepare to bypass any Russian U.N. veto and attack Damascus, there is little chance of Putin’s support. But his words may herald new efforts to overcome great power rivalries that have let Syria descend into bloody chaos.

At the same time, Moscow said it had sent a warship it calls a “carrier killer” to the eastern Mediterranean, where a U.S. fleet is waiting for Congress to approve orders from President Barack Obama to launch punitive strikes against Syrian President Bashar al-Assad following his forces’ alleged use of poison gas.

Putin’s remarks on the eve of a G20 summit in St. Petersburg stressed Russia did not share Obama’s conviction that Assad has resorted to chemical warfare – he noted suggestions the August 21 gassing was instead the work of al Qaeda-linked rebels.

And only proof, plus backing in the U.N. Security Council that depends on Moscow, would justify using force, he added. Nonetheless, in saying he did “not rule out” his support, Putin gave a shot of warmth to relations with the West that the Syrian conflict has helped chill to levels recalling the Cold War.

Russian support for military strikes on Syria could actually be the best way of preventing them happening. The possibility of losing Russia’s protection will probably alarm Assad even more than the threat of attacks. If the Obama administration was to turn its attention to a political strategy instead of obsessing over target lists, it would see an important opening in Putin’s comments and grab hold of it.