THE INITIATIVE to eliminate Syria’s chemical arsenal will advance another step Tuesday when the first team of inspectors from the Organisation for the Prohibition of Chemical Weapons (OPCW) arrives in Damascus. The previously obscure agency, based at the Hague and charged with implementing the Chemical Weapons Convention, adopted this weekend a plan under which Syria’s capacity to produce chemical munitions would be destroyed by Nov. 1 and all of its bombs and precursors eliminated within eight months.

The quick action by the OPCW was the latest of several encouraging developments in the Obama administration’s joint effort with Russia. The U.N. Security Council unanimously passed Friday a resolution mandating the elimination of the Syrian stockpile , albeit without an explicit enforcement mechanism. The regime of Bashar al-Assad delivered a declaration of its stockpile that officials say was broadly in keeping with outside assessments, if not necessarily complete.

Still, there remain grounds for concern about whether the disarmament plan can succeed and about the collateral damage caused by the Obama administration’s embrace of it. To begin with, many experts are skeptical that the timetable can be met. The OPCW has only 150 inspectors on staff. They will have to visit numerous sites across a country in the middle of a civil war.

Of more concern is the possibility that the Assad regime will attempt to deceive inspectors and preserve parts of its arsenal. It has reportedly been moving chemical weapons around ever since President Obama threatened airstrikes last month. As The Post’s Michael Birnbaum has reported, the OPCW is not well prepared to respond to noncooperation. If a government alleges that not all sites or weapons have been declared, the agency would have little recourse other than to refer the matter to its inspector general and 41-nation executive ­council.

Russia, for its part, has made clear that it will not support U.N. action against Syria unless, as Foreign Minister Sergei Lavrov put it, violations are “serious enough to merit punishment” and “proven by 100 percent.” That sounded like a virtual invitation to cheat.

The elimination of Syria’s chemical arsenal, one of the largest in the world, would be an important achievement in its own right and would lessen the dangers of the ongoing civil war. But it would not end that war, nor the continuing slaughter of civilians by the Assad regime. On the contrary: The Obama administration’s decision to partner with Russia rather than carry out military strikes appears to have been a final straw for a number of large Syrian rebel factions, which have broken with their Western-backed leaders and joined an Islamic alliance that includes a faction of al-Qaeda. Unless reversed, that would make the prospect of a political settlement to the war, which Mr. Obama promised to pursue, more remote than ever.

Mr. Obama, who dismissed the conflict as “someone else’s civil war” in his U.N. address last week, may have traded U.S. influence over the outcome for a chance to eliminate a chemical weapons stockpile. If so, his administration has a much larger stake than any international agency in accomplishing the disarmament.