As Russia and Turkey seek closer ties, not all the leverage in Kremlin's hands

Easing tensions between Ankara and Moscow would seem to benefit both Mr. Erdoğan and Mr. Putin. But Turkey also presents a complicating factor to the Kremlin in its dealings with Turkic peoples at home and abroad.

When Turkey shot down a Russian bomber over Syria last November, leading to the death of its pilot, relations between Moscow and Ankara collapsed in a cloud of mutually-acrimonious rhetoric, ruptured economic relations, and warnings of dire political consequences to come.

But there was one conspicuous exception.

Leaders of Russia's oil-rich Volga River ethnic republic of Tatarstan declined to issue any statement of political solidarity with Moscow in the quarrel. Nor did they suspend any of the major Turkish investments – including banks, construction firms, and industry – that are helping to power the region's impressive economic development. Since the 1990s, Turkey has been a major investor and partner for the Tatars, a Turkic-speaking minority within Russia who have strong bonds of cultural and ethnic kinship with the Turks.

That fact was undoubtedly in the back of Russian President Vladimir Putin's mind as he met today with Turkish leader Recep Tayyip Erdoğan in St. Petersburg Tuesday in what could be a historic turnabout in the currently sour relations between Moscow and Ankara.

The Tatars are just one among a bewildering array of Turkic-related former Soviets who may make Russia's wooing of Turkey a double-edged sword for Moscow. Turkey offers prospects for dynamic economic growth if it joins the Moscow-led Eurasian Economic Union (EEU), a two-year-old, five-member free trade zone stretching from the Baltic to the Pacific. But its influence among Turkic peoples also raises the risk of divided loyalties in an expanded bloc.

"Whatever direction Putin and Erdoğan decide to take, we have to acknowledge that Turkey has been here for some time," says Irina Zvyagelskaya, an expert with the official Institute of Oriental Studies in Moscow. "The economic prospects of linking Turkey with the EEU are really filled with prospects. But politically, what Erdogan is doing, the benefits are not so clear."

There are major implications for Turkey's involvement with anti-Assad forces in Syria's civil war, and Russia is anxious to revive the "TurkStream" gas pipeline, under the Black Sea to Europe, which was suspended amid souring ties last year but apparently is now back on.

In the longer term, Mr. Putin is dangling the prospect of greater political and economic integration with the EEU. Though regarded as a lightweight European Union-imitator in the West, the EEU might potentially grow into a powerful economic force.

Russian experts say the present moment, in which Turkey feels rebuffed in its desire to join the EU and is accusing the US of complicity in last month's abortive military coup against Mr. Erdoğan, presents a major opportunity for Moscow to draw Turkey into deeper association with its own continent-spanning economic union.

But Turkey also presents a set of priorities that could conflict with Russia, due to its sway among the "Turkic World" of peoples related to modern Turks, from the Gagauz minority in Moldova, Crimean Tatars, numerous groups in Russia's restive north Caucasus, Azeris, Kazakhs, Tatars, and many of the indigenous nations inhabiting Russia's Siberia and far east.

Turkey has been actively courting many of these groups since the collapse of the USSR, stressing historical, cultural and linguistic ties along with prospects for economic investment.

The Tatars of Russia are just one example. "The relationship between Tatar leaders and Turkey is very important, and nobody here wanted to see it disrupted," says Alexei Dyomin, deputy editor of Eurasia Daily, an alternative news service in Tatarstan's capital of Kazan. "Fortunately this potentially divisive problem seems to be sorting itself out, luckily for everyone involved. For Moscow, it's of utmost importance to maintain stability in Tatarstan."

"Under normal circumstances, greater Turkish involvement with its ethnic kin around the former Soviet Union would be something to welcome," says Ms. Zvigelskaya. "But Erdoğan, with his wild mood swings, introduces a political element that's quite uncertain. Some Turkic nations, like Kazakhstan, want to develop their relations freely with the West, as well as maintaining good ties with Moscow. If things go from bad to worse between Erdoğan and the US, as it looks like they could, they might not want to get dragged into that."

Some experts suggest the St. Petersburg meeting is mostly theater, enabling both Putin and Erdoğan to signal to the West that they have alternatives, without actually committing themselves to much.

"Really, when you look at the damage that's been done to Russo-Turkish economic relations in the past few months, it will take a long time just to restore things to their previous level," says Andrei Kolesnikov, an expert with the Carnegie Center in Moscow.

"The history of Russia's relations with Turkey didn't begin yesterday. It's centuries old, and it's always been extremely complicated," says Mr. Kolesnikov. "That's not likely to change."