With Turkey’s economy in a downward spiral and U.S. President Donald Trump vowing to enforce punishing tariffs and sanctions, one of America's oldest and most strategic military alliances in the Middle East is being put under even more severe stress – with immense political and regional implications for both countries.

Update: Trump Threat of Even More Sanctions Sends Turkey's Lira Down Again

As the Turkish lira hit record lows earlier in the week, President Recep Tayyip Erdogan accused Trump in The New York Times of stabbing him in the back. Turkey, the defiant president warned, would “start looking for new friends and allies.” The statement was a thinly veiled reference to Russia, which has called for dropping the dollar as the main international currency, a move that could help bolster the lira.

However, ties between Turkey and the U.S. may not be so easily upended – thanks largely to NATO. Turkey has been a key U.S. ally since 1946 and the Incirlik Air Base, which the two countries share and which houses U.S.-controlled nuclear weapons, serves as the key staging ground for the U.S.-led anti-ISIS coalition in the Middle East.

Aaron Stein, a Middle East and Turkey expert at the Atlantic Council, argues that “there is no indication Turkey wants to blow this up yet,” emphasizing the fact that Erdogan is all but out of leverage in this current spat.

“Turkey’s primary leverage is to end the anti-ISIS coalition from operating out of Incirlik,” Stein says. Turkey has been a NATO member since 1952 and Incirlik can only be used for NATO missions. “But it’s an empty threat, as the operation is winding down anyways; much of it is now out of Jordan and Erdogan doesn’t want to be seen as aiding ISIS.”

Trump hitting Turkey with metal tariffs was “low-hanging fruit” designed to create “maximum pain” to push Turkey to release the imprisoned American pastor Andrew Brunson and leave Erdogan with few options.

In March this year, the Wall Street Journal reported the U.S. military was already scaling back its presence at Incirlik, quoting an official who linked the drawdown to U.S.-Turkish tensions over Trump’s Syria policy. Stein cautions, however, that the base will not shutter so quickly, given its international status; he notes that Spain, for example, has a Patriot missile battery there for Syrian operations.

After the failed coup in 2016, anti-American rhetoric and anger spiked within the Turkish government, leading to public discussion of the U.S. removing its nuclear weapons from Turkey – especially as Turkey unilaterally shut down the air space over the base during the coup. “Does it seem like a good idea to station American nuclear weapons at an air base commanded by someone who may have just helped bomb his own country’s parliament?” asked Jefferey Lewis in Foreign Policy in July 2016.

However, Stein argues that any threat of kicking the U.S. out of Incirlik or limiting operations is overblown; operations out of Incirlik are governed by multinational agreements, including NATO, and require parliamentary approval within Turkey. The bigger issue here, Stein notes, would be if Erdogan threatens to limit NATO operations out of Incirlik, which doesn’t appear to be on the table yet.

Additionally, the nuclear weapons in Turkey can only be used with NATO consensus and any drawdown of that arsenal would require not only a NATO consensus but also Russian involvement – making them largely a non-issue.

A NATO exit?

Against the background of the current U.S.-Turkey spat, Erdogan has actually been committing to an increased role in NATO. He has proposed using the Turkish army’s military headquarters in Istanbul for the new land command structure of NATO, and Turkey will likely send a deputy commander and military advisers to NATO’s newly-launched training mission in Iraq.

Turkey is also set to take command of NATO’s Very High Readiness Joint Task Force (VJTF) in 2021. At the NATO Summit in Brussels in July Erdogan said Turkey is doing well in terms of military spending, with 1.8 percent of its GDP going to defense. He also backed Trump's push to up the 2 percent goal to 4 percent – a clear move away from Russia.

However, Erdogan’s new NATO commitments are not necessarily the whole story, he’s playing a double game, also taking Turkey away from the alliance while Trump publicly criticizes NATO and questions its relevance.

Turkey's future in NATO in doubt?

Turkey has been willing to ruffle its NATO allies for a while now, with plans for a $2 billion purchase of Russian-made S-400 surface-to-air missiles. NATO has clearly said the purchase is incompatible with allied systems and NATO restrictions on the use of Incirlik. Fears persist that the S-400 radar could capture the stealth signature of the F-35 and help Russia to thwart that technology.

New Hampshire Democrat Jeanne Shaheen said in the U.S. Senate in July, while trying to block the delivery of U.S. F-35s to Turkey: "NATO partners need these F-35s to counter Russian activity. We would be handing this technology over to the Kremlin if we granted Turkey these planes, and Congress will not stand for it."

On Monday, Trump signed a sweeping defense bill that blocked delivery of those F-35s, which Turkey has already largely paid for – until Brunson is returned.

However, Jacob Funk Kirkegaard of the Peterson Institute for International Economics points out to Bloomberg, that Erdogan may simply be following Trump’s lead with public moves that appear to defy NATO conventions. "For an administration or a president that doesn’t give much value to NATO, the value of Turkey as a staunch NATO ally also has declined,” claims Kirkegaard. “The Trump administration isn’t going to walk an extra mile to save an organization it doesn’t value.”

Erdogan too appears to harbor an anti-NATO sentiment. Therese Raphael adds, “Erdogan never quite recovered from his anger at the way his allies seemed to sit on the fence in the hours after an attempted coup was announced in July 2016.” Erdogan, with typical bluster, has been pushing a plan, which Russia backed on Monday, to dump the dollar in retaliation to U.S. sanctions and begin bilateral trade using local currencies.

“Shame on you, shame on you,” Erdogan declared at a rally last week in response to Trump. "You are swapping your strategic partner in NATO for a pastor.” The question now is whether or not Turkey will be willing to split with NATO and further wreck its own economy in order to keep a pastor in jail.