Erdogan appears to be using Turkey's role as a mediator in the Ukraine war and its ability to veto new NATO members as an opportunity to air a variety of grievances and to force other nations to take action against groups the Turkish government views as terrorists, including Kurdish militants.
Amplifying his strongman image by focusing on international disputes also could resonate domestically as Turkey gears up for a general election next year.
Here's a look at Erdogan's latest brinkmanship and what he can hope to gain:
WHAT DOES TURKEY WANT?
Turkey, which commands NATO's second-largest army, is pushing for long-sought demands that Sweden - and to a lesser extent Finland - crack down on entities that Ankara says are linked to the Kurdistan Workers' Party, or PKK.
In threatening to block the addition of the two Nordic nations to the Western military alliance, the Turkish government also wants them to end their alleged support to the People's Protection Units, or YPG, a Syrian Kurdish militia.
The PKK is considered a terrorist organization in Turkey, Europe and the United States. It has led an armed insurgency against the Turkish state since 1984, and the conflict has killed tens of thousands of people. Turkey says the PKK and the YPG are one and the same.
Turkey is seeking the extradition of wanted terror suspects from Finland and Sweden. The two NATO hopefuls reject accusations that they support the PKK or other terror groups.
Another key demand is the lifting of weapons sales restrictions that several European countries, including Sweden and Finland, imposed on Turkey following a 2019 incursion into Syria to act against the YPG.
Merve Tahiroglu, Turkey program coordinator at the Project on Middle East Democracy, said Erdogan believes that NATO needs Turkey, putting him a position to bargain.
``They (NATO allies) want to demonstrate to Russia that NATO is more united than ever and that even Erdogan's Turkey won't be able to spoil that. So Erdogan knows that he can get away with it,`` Tahiroglu said.
WHY THREATEN A NEW OFFENSIVE IN SYRIA NOW?
Turkey has carried out three major incursions into Syria since 2016 that have strained its relations with the United States. Washington views Syrian Kurdish groups as key allies in the fight against the Islamic State group, but Turkey regards them as terrorist organizations.
Erdogan announced plans Monday for a new Turkish offensive in northern Syria to create a 30-kilometer deep safe zone along its southern border. The long-stated aim would be to push the YPG militia away from Turkey's borders.
The timing suggests such an offensive could be used to rally nationalist voters while also providing an avenue for the momentum created by Turkey's role as a mediator in the Russia-Ukraine war to further Ankara's demands in the NATO negotiations.
Michael Tanchum, a senior fellow at the Austrian Institute for European and Security Policy, said the Turkish government thinks its NATO allies do not fully appreciate the threat the PKK and its branches pose to Turkey.
At the same time, Turkey enjoys close relations with both Moscow and Kyiv. Amid the war in Ukraine, its position ``provides Ankara with some leverage to attempt to address these issues of great concern for the Turkish Republic,`` Tanchum said.
But another incursion into Syria on top of Turkey's opposition to Sweden and Finland joining NATO could unravel the ``goodwill'' Erdogan built following Russia's invasion of Ukraine, according to Tahiroglu of the Project on Middle East Democracy.
``He has certainly reinforced the idea that many NATO allies had that Turkey is a problematic ally under Erdogan,`` Tahiroglu said.
HOW DOES GREECE FIGURE INTO THIS?
Nominal NATO allies Greece and Turkey are regional rivals with longstanding disagreements on a range of issues, from maritime boundaries in the eastern Mediterranean to the future of ethnically divided Cyprus. Tensions between them flared in 2020 over offshore energy rights.
Erdogan was angered by comments Greek Prime Minister Kyriakos Mitsotakis made during a recent visit to Washington. The prime minister suggested while addressing Congress that the United States should not sell F-16 jets to Turkey to avoid creating ``a new source of instability'' on NATO's southeastern flank.
In response, Erdogan said he would no longer speak to Mitsotakis and would cancel a Strategic Council Meeting between their two governments.
Turkey's president referred to the animosity with Greece in discussing his opposition to Sweden and Finland's NATO applications. Erdogan said his country made a mistake by approving Greece's reentry into the alliance's military wing in 1980 and he is determined not to make the same mistake with Sweden and Finland.
Speaking at this week's World Economic Forum in Davos, Switzerland, Mitsotakis said it would be ``a mistake if Turkey continues to use these (NATO) negotiations to extract sort of benefits for its own national interests.''
WHAT ROLE DO ELECTION POLITICS PLAY?
Turkey is set to hold next year's presidential and parliamentary elections by June 2023 at the latest. Incursions into Syria to drive out the YPG bolstered support for Erdogan in past elections. The Turkish leader may be hoping to again rally nationalist votes at a time when the country's economy is in decline, with inflation running at nearly 70%..
Erdogan also saw his popularity increase previously when he appeared to stand up to Greece and other Western nations.
``I think his plan currently is to demonstrate to his voter base that he can strongarm the U.S. and NATO allies,`` Tahiroglu said. ``And he's empowered to do this, to act this way, because these allies have been appeasing him since the beginning of the Ukraine war.''