NICOSIA, Cyprus (AP) — Turkish Cypriots vote on Sunday in a leadership runoff that could decide whether they retain more control over their own affairs or steer even closer to an increasingly domineering Turkey.

Veteran incumbent Mustafa Akinci, 72, backs the long-held federal framework for a deal with rival Greek Cypriots to reunify ethnically divided Cyprus. He’s also a champion of Turkish Cypriots who oppose Turkey’s complete domination of their affairs.

His hardline challenger Ersin Tatar, 60, advocates fully aligning Turkish Cypriots with Turkish policies, such as pursuing a two-state deal instead of a federation.

Here’s a look at what’s at stake:

THE PEACE PUZZLE

A 1974 Turkish invasion triggered by a coup aimed at union with Greece split the eastern Mediterranean island along ethnic lines. Nine years later, Turkish Cypriots in the northern third declared independence, but are only recognized by Turkey, which maintains a strong military footprint there.

Since then, the agreed-upon arrangement that would restore Turkish Cypriots to the international fold is a federation of two separately administered zones. But nearly half a century of U.N.-mediated talks to cobble a deal together have stumbled on several core issues.

Those include a demand for Turkey to retain military intervention rights and a permanent troop presence. The majority Greek Cypriots also oppose a Turkish Cypriot demand for equal say at all levels of federal government.

Akinci says that despite the difficulties federation is the only path to peace. But Tatar mirrors Turkey’s view that both sides must look at new options, including a two-state deal.

The winner’s first test will be a planned meeting under U.N. Secretary General Antonio Guterres, bringing together the two sides with ‘guarantors' Greece, Turkey and Britain to scope out the chances of resuming peace talks.

But the final say on key issues such as intervention rights rests with Ankara, on which Turkish Cypriots are economically and militarily dependent.

THE ENERGY QUESTION

Turkey, Greece and Cyprus are heavily at odds over potential offshore gas and oil reserves. With much military muscle flexing, Turkey has laid claim to areas of the sea where Greece and Cyprus’ internationally recognized Greek-Cypriot government say they have exclusive economic rights.

Ankara says it’s got every right to look for energy reserves there and that it's also defending Turkish Cypriots' rights. The standoff has ratcheted up military tensions between Greece and Turkey.

A Cyprus peace deal would go a long way towards easing those tensions and enabling maritime border deals that would unlock the eastern Mediterranean’s huge potential as a possible gas exporter to energy-hungry Europe and beyond.

Akinci says peace talks should include negotiations on sharing any future gas proceeds. Tatar takes that a step further by insisting an energy deal should come first. Greek Cypriots say Turkish Cypriots’ share to a potential gas bounty is already guaranteed.

TURKEY’S HAND

Last week’s first round of voting took place under the cloud of Turkey’s alleged meddling to rally support around Tatar.

In a move that also served notice over who’s pulling the strings in the north, Turkey opened to the public a beach in an uninhabited Famagusta suburb that's remained off-limits and under Turkish military control since its Greek Cypriot residents fled the 1974 invasion.

Many Turkish Cypriots interpreted the move as Ankara trying to boost support for Tatar, while Greek Cypriots were angry at what they saw as a prelude to the Turkish Cypriots taking over the whole suburb in contravention of U.N. resolutions.

Akinci charged that the beach opening showed an unprecedented level of Turkish interference in an election and argued that it would pit Turkish Cypriots against U.N. decisions.

THE NUMBERS:

In the first round, Ersin Tatar came out on top with 32.35%, and Akinci secured 29.84%. The center-left CTP party of third-place finisher Tufan Erhurman who garnered 21.68%. has thrown its support behind Akinci. But the race could go either way.

Akinci may have CTP backing, but Tatar is courting a significant pool of voters — especially in rural areas — who may not have voted in the first round. Turnout will be a key factor. The first round saw an all-time low voter participation of 55% from a 200,000-strong electorate, and some analysts say a higher turnout might favor Tatar.