Turkey can check Russian ambitions in the Black Sea or allow it to dominate the Caucasus.

Russian and Turkish leaders Vladimir Putin and Recep Tayyip Erdoğan announced on Monday they would expand energy relations between their countries.

Russian-Turkish relations remain problematic, but the prospect of a partnership poses a strategic threat to the West.

Energy trade

Putin told a news conference in Ankara he would give Turkey a 6-percent discount on its gas imports next year.

He also announced the cancelation of the planned South Stream pipeline, which was meant to deliver Russian gas through a pipeline under the Black Sea into Europe, and said it would be diverted into Turkey instead.

Russia provides two-thirds of Turkey’s gas.

It is also helping Turkey build its first nuclear power plant.

Last year, Russia became Turkey’s second trading partner, after Germany. Total trade between the countries reached $32 billion in 2013.

Differences

The countries do have considerable differences:

Turkey calls for the overthrow of Russia’s Syrian ally, Bashar al-Assad.

It opposed Russia’s annexation of the Crimean Peninsula from Ukraine in March and has expressed concerns about Russia’s treatment of area’s native Turkic Tatars.

Turkey is also a key European ally in the transfer of natural gas from the Caspian Sea region that bypasses Russia.

Challenge to Europe

Improved Russian-Turkish relations pose a challenge to Europe beyond energy security.

As NATO’s southeastern anchor, it acts as a check on Russian ambitions in the Black Sea. Since it controls the Dardanelles, it can prevent Russia from projecting power into the Mediterranean.

It also enables pro-Western republics in the Caucasus — mainly Georgia and to a lesser extent Azerbaijan — to deepen their own relations with the West.

A Russian-Turkish coalition, by contrast, would allow Russia to dominate both the Black Sea and the Caucasus region.

Brzezinski’s warning

Former American national security advisor Zbigniew Brzezinski warned against such a possibility more than fifteen years ago in The Grand Chessboard: American Primacy and Its Geostrategic Imperatives (1997).

“Turkey’s evolution and orientation are likely to be especially decisive for the future of the Caucasian states,” he predicted.

If Turkey sustains its path to Europe — and if Europe does not close its door to Turkey — the states of the Caucasus are also likely to gravitate into the European orbit, a prospect they fervently desire. But if Turkey’s Europeanization grinds to a halt, for either internal or external reasons, then Georgia and Armenia will have no choice but to adapt to Russia’s inclinations.

Turkey’s Europeanization has grind to a halt under Erdoğan’s Islamist leadership and European Union countries remain reluctant to admit a Muslim state of almost eighty million people that would be the second largest in the bloc.

Russia, on the other hand, facing recession as a result of falling oil prices and Western economic sanctions imposed after it invaded Ukraine, is anxious for new partners and seems determined to reassert itself in the Black Sea region. Since annexing the Crimea, it has supported a separatist insurgency in the southeast of Ukraine and strengthened security ties with the breakaway Georgian territory of Abkhazia.