In a previously unscheduled visit, Israeli Prime Minister Benjamin Netanyahu is meeting with Russian President Vladimir Putin on May 14 in Sochi. Putin reportedly extended the invitation to Netanyahu because Israel had been growing concerned that Russia was preparing to transfer the S-300 air defense system to Syria within the next few months. Syria already has a relatively robust air defense system, but the addition of the S-300 air defense system would bolster its capabilities and augment the complexities attached to a potential military intervention. Also, Russian technicians would maintain and operate the air defense system, further complicating Israeli attempts to target these weapons systems without drawing itself into a broader conflict with Moscow. Russian Foreign Minister Sergei Lavrov denied that Russia had any intention to sell the S-300s to Syria. He did, however, claim that Russia was delivering an air defense package to Syria under a 2010 agreement without providing any details on whether the weapons package would include the S-300 system.
 
Russia typically threatens to sell sensitive weapons to countries branded as political pariahs by the West as a way to grab Washington's attention on issues that Moscow deems critical. This is an old game that Russia has played with the United States over the past decade, leaking potential sales of S-300 systems to Iran to demand a conversation with the United States on issues like U.S. ballistic missile defense plans in Europe. This time the original source of the leak was U.S. media, citing U.S. and Israeli defense officials. This would mark a departure from Russia's usual method in leaking such sales through Russian media or defense officials. It is possible that the United States and Israel raised the S-300 issue as a way to build up opposition to Russia and to cast Moscow as an irresponsible stakeholder in Syria. But the threat of Russian weapons sales to Syria alone appears to have been enough to compel a last minute meeting between the Israeli Prime Minister and Russian leader.
 
A day before Netanyahu traveled to Sochi, British Prime Minister David Cameron had some unusually optimistic things to say about Russian involvement in Syria. Cameron met with Putin in Sochi on May 10 and then met with U.S. President Barack Obama on May 12 in Washington to discuss Syria. Following his meeting with Putin, Cameron said that he believes Putin is "prepared to adopt a more flexible approach on Syria." Cameron admitted that Russia was far from abandoning its support for the al Assad regime but said that he was struck by Putin's willingness to consider the Western point of view on Syria.
 
The apparently positive response that Cameron was able to elicit from Putin stands in marked contrast to the United States' recent interactions with Russia. In the lead-up to U.S. Secretary of State John Kerry's visit to Moscow on May 6, speculation was building that the United States was going to try to come to an agreement with Russia on Syria, particularly since the threat of chemical weapons proliferation was filling the headlines at the time. But the meeting between Kerry and Putin was visibly strained. While in Moscow Kerry made a point to meet with Russian nongovernmental organizations — some of which were anti-Kremlin. Putin also made Kerry wait for hours before meeting with him. Russia appears to be holding onto one of its main negotiating tools — its weapons support for Syria — to pressure the United States, while Washington is using its main leverage — Western support of nongovernmental organizations in Russia — to pressure Moscow. So far, this appears to fit into the pattern of U.S.-Russian retaliatory relations.
 
That Putin responded favorably to Cameron has more to do with Russia's strategic goals for Europe than it has to do with Syria. For the first time in two decades, we have seen a warming of relations between London and Moscow, driven primarily by the two countries' expanding energy relationship. Putin may have been willing to say the right things to Cameron to make the U.K. leader appear influential to Obama, but how far Russia is willing to go in cooperating with the West on Syria is another question.
 
Russia has a strategic interest in maintaining a naval presence in the Mediterranean at Syria's Tartus port. Even as Syria fragments along ethnic and sectarian lines, Tartus would still likely remain under Alawite control, making it imperative for Russia to maintain close ties with the ethnic minority when Moscow is already a clear adversary of the Sunni rebels. Moscow is one of the few countries that can hold a conversation with the United States, still has influence in the al Assad regime and has strong intelligence capabilities on the ground in Syria that could prove critical to Western attempts to seize and secure chemical weapons stockpiles. Russia may cooperate sporadically to entice the West, by restricting fuel shipments or certain weapons transfers, but as long as the United States acts disinterested, much less confrontational, with Russia, Moscow has little incentive to sacrifice its existing influence in Syria.
 
Currently, Russia is reinforcing its supply lines to Syria. It is deploying five to six warships with support ships from its Pacific fleet to establish a permanent presence in the Mediterranean Sea for the first time since the fall of the Soviet Union. A permanent command structure in the Mediterranean would oversee a constant presence of these ships that would be rotated in from different fleets. Critically, Russia's reinforced naval presence in the Mediterranean would not only entrench Russian interests in the region but could also provide a secure line of supply for the Alawites in Syria unless foreign groups want to risk a military conflict on the Mediterranean by trying to blockade these shipments.
 
Moreover, the conflict in Syria has likely surpassed diplomatic aspirations to negotiate a political exit for al Assad. The Alawites are engaged in an existential fight against Syria's Sunni majority, and their fate is joined by a substantial number of Shia in Lebanon and Iraq. In the absence of any legitimate offers for amnesty or protection for Alawites in Syria, there is little reason for them to give up the fight at this stage. On the other side of the conflict, Syria's Sunni population, emboldened by a broader Sunni regional effort to crack Iran's Shiite arc of influence, is not likely to cease fighting after a great deal of blood has already been shed, only to see a settlement in which power is shared with its sectarian adversaries. At most, the outside powers could attempt to come to an agreement to limit external support for both sides of the conflict.
 
But even if the United States and Russia can come to terms, which is looking unlikely, regional players like Saudi Arabia, Iran and Turkey have a vested interest in this fight and will also be driven by sectarian interests. The United States, Russia, the United Kingdom and others will continue to host conferences aiming for a political settlement to preclude the need for a foreign military intervention, but in the end, this is a struggle that will be decided on the battlefield in Syria, not in a diplomatic negotiation conducted by foreigners.