If the current Turkish President Recep Tayyip Erdogan loses the elections on May 28, the country could face major changes in its relationship with countries around the world.
Under Erdogan's leadership, Turkey has angered Western allies by forging close ties with Russia.
He also sent Turkish troops into conflicts in Iraq, Syria and Libya.
Opposition candidate Kemal Kilicdaroglu promises to be more pro-Western and to intervene less abroad.
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How could Turkey treat Syrian refugees?
Turkey is home to an officially registered 3,7 million Syrians, having fled the civil war in their homeland - as well as refugees from other countries such as Afghanistan.
President Erdogan said that Turkey "cannot cope" with that number.
Both he and Kemal Kilicdaroglu state that they want to "normalize" relations with Syria so that the refugees can be returned.
But that would mean a return to life under the authoritarian regime of President Bashar al-Assad.
This month, Turkish media quoted Kilicdaroglu as saying, "I will bring all the refugees home as soon as I am elected president, period."
He threatened to scrap the agreement with the European Union, according to which Turkey agreed to accept millions of refugees from Syria, preventing them from crossing into EU countries and seeking asylum there.
Kilicdaroglu says the EU has not fulfilled its part of the deal.
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How could Turkey's relations with the West change?
Since the Republic of Turkey was founded in 1923, it has traditionally been an ally of the Western powers.
Turkey has one of the largest armies in NATO, the West's defense alliance. It also applied for EU membership.
However, President Erdogan regularly describes Western countries as "imperialist" or "unjust".
Under his rule, Turkey deepened its relations with Russia.
In 2019, it purchased a large number of Russian S-400 air defense missile systems.
In retaliation, the US banned Turkey from participating in the international consortium working to develop the F-35 fighter jet.
Turkey is also blocking Sweden's entry into NATO after Russia's invasion of Ukraine, claiming that Sweden is harboring enemies of the Turkish state.
If Kilicdaroglu is elected president of Turkey, he will focus on mending relations with the West, says Galip Delay of Chatham House, a London-based foreign policy think tank.
"He will cultivate more formal relations with the West." Foreign policy will be less personal than under President Edrogan and more diplomatic."
Kilicdaroglu says that as president he will renew Turkey's request to join the EU and ensure that the decisions of the European Court of Human Rights are respected in Turkey.
But by threatening to pull out of an agreement with the EU for Turkey to host millions of Syrian refugees, he has shown he is ready to confront Western powers.
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How could Turkey's policy towards the war in Ukraine change?
Since the beginning of the war, Turkey has been trying to balance support for Russia and Ukraine.
It refused to impose Western sanctions on Russia, but sold Bajraktar military drones to Ukraine.
Turkey also played the role of mediator in the agreement that allowed the export of Ukrainian grain across the Black Sea to the rest of the world.
If Kilicdaroglu becomes president, he may offer less support to Russia, says Hamdullah Bajkar of the University of Exeter.
"He wouldn't have such a close relationship," he says.
"On the other hand, he wouldn't even become an enemy of Russia."
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How could Turkey's relations with the countries of the Middle East change?
Since 2008, Turkey has sent armed forces to conflicts in Iraq, Syria and Libya.
In Libya, its forces are supporting the Government of National Unity - based in the capital Tripoli - against rebel forces in the east of the country led by General Haftar.
"Turkey has long-standing business interests in Libya and wants peace to reign in the country," says Doctor Begum Zorlu from City University in London.
In Iraq and Syria, Turkish forces are confronting a group called the People's Protection Units (JPG), as well as elements of the Kurdistan Workers' Party (PKK), which is outlawed in Turkey and many other countries as a terrorist organization.
The Turkish government suspects that JPG supports the PKK.
This angered the US, which sees the JPG as one of its key allies in Syria because it opposes the regime of President Bashar al-Assad.
Kilicdaroglu claims that as president he would lead a "non-interventionist" foreign policy.
However, it is unclear whether he would withdraw Turkish forces from Iraq, Syria or Libya.
"There are many nationalists in Kilicdaroglu's opposition coalition who would oppose it," says Dr. Zorlu.
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How could Turkey's relations with China change?
Turkey's relationship with China revolves around trade and finance.
It joined China's Belt and Road Initiative to strengthen trade ties and took loans from China.
China sent its first covid vaccines to Turkey during the pandemic.
The Erdogan administration has been careful not to anger the Chinese government and has kept quiet about China's alleged repression of the Uyghurs - despite them being considered a Turkic people.
Kilicdaroglu claims that as president he will discuss this problem with the Chinese government.
However, Bajkar says, "Kilijdaroglu is now vocal about the Uyghurs, but it is possible that he will be quieter if he comes to power."
Would Turkey's "soft power" policy in Africa change?
In the last 20 years, Turkey has opened new embassies in dozens of African countries.
There she exerted her soft power, opening schools across the continent and granting scholarships to Africans to study in Turkey.
It sold defense equipment such as drones to African governments.
Dr. Zorlu says that Erdogan's government is active in Africa because he is trying to strengthen Turkey's status as a protector of poor countries.
"President Erdogan is trying to build a coalition of countries that feel abandoned by the West," she says.
However, she says, Turkey's policy towards Africa will most likely remain the same even if the president changes.
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