When it comes to European integration in its neighborhood, Russia has a clear double standard.
Georgia, Moldova, and Ukraine have had to battle relentless opposition from Moscow every step of their path toward closer ties with Europe.
Meanwhile, Balkan countries like Macedonia, Montenegro -- and particularly Serbia -- have largely been left to pursue closer relations with the European Union, including possible membership, in peace.
The harsh approach toward the former Soviet countries that Russia historically dominated and the softer line for the kindred Slavic lands of the Balkans is rooted in a deeper strategy aimed at increasing Moscow's influence within the EU, analysts say.
"Russia has very different strategies when it comes to their former fellow republics in the Soviet Union -- this is part of their previous sphere of influence," says Dmitar Bechev, director of the Sofia office of the European Council on Foreign Relations (ECFR). "The Balkans are a level up [from that]. I think it is a foregone conclusion that one way or another [Balkan countries] will be integrated into the EU. But, having said that, Russia looks at the EU as a set of countries and so it sees an opportunity to have more members who are friendly."
The Kremlin's "Trojan horse" strategy was on full display when Serbian Prime Minister Aleksandar Vucic visited Moscow for two days of talks on July 7-8. Belgrade, Vucic said, was bent on EU membership but also did not intend to "damage its good, friendly relations with Russia."
Working From The Inside
Serbia has made dramatic strides toward the EU, signing an Association Agreement in 2008 and becoming a candidate for membership in 2012. At the same time, Moscow has augmented its considerable influence in the country.
When Vucic was forming his new government earlier this year, Moscow lobbied hard and successfully to have outgoing Prime Minister Ivica Dacic -- considered one of Serbia's most pro-Russia politicians -- given a powerful post. He was named deputy prime minister.
A symbolic pipe is prepared for the ceremony kicking off construction of the South Stream gas pipeline near the Serbian village of Sajkas in November 2013.
In an interview with ITAR-TASS on the eve of Vucic's visit to Moscow, Russian Ambassador to Belgrade Aleksandr Chepurin noted that Gazprom's oil refinery in the Serbian city of Novi Sad alone accounted for 14 percent of Belgrade's budget revenues.
The Balkan region is essential to Russia as an energy-transit corridor hosting the South Stream natural-gas pipeline. Russian Foreign Minister Sergei Lavrov is touring the region this week, launching his trip with a visit to Sofia for talks focused on South Stream. Vucic said in Moscow that he expected an agreement on the Serbian portion of the project to be signed "soon."
Belgrade-based analyst Boris Varga says Belgrade remains dependent on economic support from Moscow, support the Kremlin "is not willing to offer without political concessions."
This is why the ECFR's Bechev believes Moscow does not object to Serbia's European ambitions. "The rule of law and the attitudes of the elites [in Serbia] are not up to what you might call European standards," he says. "In other words, obviously Russia has a lot of influence to wield -- they can call people, they can bribe people, and they can build influence from within. So that's why I don't think Russia will object at any point to EU enlargement [in the Balkans]. On the contrary, they will embrace enlargement to the Balkans, and it has embraced enlargement to the Balkans as an opportunity to build its influence inside the union."
Bechev notes that Moscow has long been building its influence within the EU, through other "Trojan horses" like Bulgaria, Cyprus, and Greece, as well as by building up pro-Moscow lobbies in critical EU countries like Germany, Italy, and the United Kingdom.
Will Belgrade Have To Choose?
But Moscow is also keeping its options open and is poised to scuttle Belgrade's EU ambitions should the need arise.
Jelena Milic, director of the Center for Euro-Atlantic Studies in Belgrade, notes that Serbia's potential EU membership is still a decade away and that Moscow cannot count on Belgrade's reliability that long. "My thesis is that the whole thing is much too long-term and that the Russians will actually want to stop the process of Serbia's European integration," she says. "It won't wait for Serbia to squeeze into the EU to be used as a Trojan horse, but will stop the process beforehand."
Milic says Moscow is already covertly funding "anti-EU structures" in the Balkans, including university programs, nongovernmental organizations, and political parties with the aim of reducing public support in Serbia for European integration.
Meanwhile, the crisis in Ukraine has tested Belgrade's policy of pursuing good relations with both Moscow and the EU.
Serbia has not joined EU sanctions against Russia over the situation and has praised Russian President Vladimir Putin's public initiatives for resolving the violence in eastern Ukraine. At the same time, it has endorsed EU statements supporting Ukraine's territorial integrity, including the Black Sea peninsula of Crimea that Russia annexed in March.
This dilemma will become sharper next year when Serbia takes over the rotating chairmanship of the Organization for Security and Cooperation in Europe (OSCE), the main international organization tasked with regulating the Ukraine crisis and frozen conflicts throughout the former Soviet Union.
Dusan Lazic, a former Serbian ambassador to Ukraine, says the crisis there is already "one of the most controversial international topics" in Serbia. "And we are going to be in a situation where we will be coordinating the work of OSCE while trying to find solutions that are acceptable to the East and the West," he says. "That is not something easy to achieve, because the Russian side will try to bring its position to the fore. The Serbian OSCE chairmanship will be a huge challenge for our policy and for our relations with other countries."
Lazic concludes, "It will not be easy at all to coordinate all that and to bring all the positions and interests together."
RFE/RL Balkan Service correspondents Milos Teodorovic, Branka Mihajlovic, and Ljudmila Cvetkovic contributed to this report from Belgrade