In the latest effort to end Syria's five-year civil war, talks between the government of Syrian President Bashar Assad and rebel opposition groups broke down almost as soon as they began Monday after both sides charged the other with negotiating in bad faith. It was an inauspicious start to what had been billed as the last best chance for peace in a conflict that already has killed some 250,000 Syrian civilians and driven millions more into exile. At this point it's too soon to know whether the talks can be revived, but a failure of the U.N.-sponsored negotiations in Geneva clearly would represent a setback for U.S. policy in the region.

There are indications that is exactly what the Assad government and its Russian allies wish to see happen. On the very day the talks were set to open officially, Syrian government forces, backed by hundreds of Russian airstrikes, attacked rebel positions in and around the northern city of Aleppo in what looks like a deliberate attempt to derail the peace process. The London-based Syrian Observatory for Human Rights called it the first major government offensive since Russia launched its air campaign in support of Mr. Assad in September and said dozens of civilians have been killed or wounded.

The attacks prompted opposition leaders to refuse to even meet with U.N. special envoy Staffan de Mistura, who is mediating indirect talks between the two sides. The rebels insist negotiations are impossible until Mr. Assad halts the offensive, releases hundreds of prisoners and allows the delivery of humanitarian aid to thousands of civilians trapped by the fighting. But the Syrian delegation in Geneva dismissed those demands out of hand, forcing Mr. de Mistura to concede on Tuesday that the talks could collapse while still in the “preparatory phase” if the two sides can't resolve the impasse.

It should come as no surprise that Mr. Assad would happily torpedo the talks as long as he can blame his opponents for prolonging the conflict. Over the last year his forces have managed to steadily reverse U.S.-supported rebel gains on the ground with Russian and Iranian backing while giving the Islamic State a more or less free hand to operate in the areas it controls. His strategy seems to be to eliminate his domestic opposition first so that afterward he can present himself as the only viable alternative to an ISIS takeover of the country.

Russian President Vladimir Putin has enabled those ambitions by stationing military aircraft and troops in Syria under the pretense of fighting ISIS, and he has managed to get away with it so far despite the fact that the vast majority of Russian airstrikes, like the ones launched Monday on Aleppo, have targeted Syrian opposition groups supported by the U.S. and its allies rather than Islamic State militants. Mr. Putin may claim he's engaged in Syria as a partner of the West, but it's clear his real intent is to thwart U.S. policy in the region and undercut international efforts to force Mr. Assad's exit from the scene.

No wonder British Foreign Secretary Philip Hammond recently told journalists that “everything we are doing is being undermined by the Russians.” Mr. Hammond charged Russian forces in Syria with “posing as the co-sponsors of the political process, and at the same time bombing the people who we believe are the future of Syria.” Another diplomat complained that “the Russians and [the Assad] regime want to push the opposition out of Geneva so the opposition bears the responsibility for the failure.”

That's a bleak assessment of what may lie ahead for millions of Syrian civilians who have seen their country devastated by years of civil war and the rise of ISIS. Unfortunately, Mr. Assad and his Russian and Iranian backers have done nothing to contradict it. The U.S. and its partners must continue to push for a negotiated end to the conflict that addresses the humanitarian catastrophe currently unfolding in Syria. But they should be under no illusions that Mr. Putin's Russia will be part of the solution to a problem that will only get worse as long as the war continues.