Why Is Russia Still Arming Syria? The slim hope generated two weeks ago when the United States and Russia announced plans for an international conference aimed at ending Syria's increasingly virulent civil war is fast fading - and Russia is a big reason. Instead of using its leverage as Syria's enabler and defender to move President Bashar al-Assad toward a negotiated solution, Russia recently sent him advanced antiship cruise missiles, and there is fresh talk now of advanced A-300 air defense weapons. The Russians have also augmented their naval presence in the region. The delivery of antiship missiles was ill-timed, to say the least. As long as Mr. Assad can count on military and political support from Russia, he has no incentive to agree to a cease-fire or a political transition. In a rare interview with a foreign newspaper - Clarín in Argentina - on Saturday, he seemed to dismiss the possibility that the conference could make serious progress toward peace and backed away from suggestions by Syrian officials that the government would negotiate with armed opponents. Russia has a major interest in retaining its naval port in Syria to protect oil and gas markets, and it is understandable that it would want assurances in this regard in any post-Assad scenario. But it also shares a strong common interest with the United States in ensuring that Syria does not end up as a failed state dominated by jihadists. By agreeing to co-lead this conference, President Vladimir Putin has put Russia's credibility on the line just as much as President Obama has put America's. Russia is not the only obstacle to a successful outcome in Syria. Among the opposition, extremists - like Hezbollah, which is backed by Iran - are playing a growing role. The so-called moderate opposition working with the West and its Arab allies is fractured, increasingly tarnished by accusations of atrocities (as are the pro-Assad forces) and undecided about whether to attend the peace conference. The week ahead is critical. Most of the major countries and groups with an interest in Syria are holding meetings that will determine whether the conference can even take place, much less make any progress. Secretary of State John Kerry is expected to explain the plans for the conference on Wednesday in Jordan to the anti-Assad alliance of Western and Arab countries. He will need to do a better job of clarifying the American vision, and organizing the allies, than Washington has done so far. The opposition forces are scheduled to meet in Istanbul on Thursday, followed by an Arab League meeting in Cairo. For the opposition to boycott the conference would hand a significant propaganda victory to Mr. Assad.