The tense relationship between the United States and Turkey is reaching an inflection point. As the Turkish government has taken an increasingly authoritarian turn and made questionable foreign policy choices in recent years, Washington has tried to exercise strategic patience and engage Turkish leadership to resolve differences between the two countries. But that patience is wearing thin, as Ankara has repeatedly failed to respond to Washington’s concerns—chief among them right now the imprisonment of Andrew Brunson, a Christian pastor from North Carolina, on specious terrorism charges. The handling of the Brunson case, which came to a head last week when he was moved to house arrest rather than released, will affect the future of bilateral ties. If negotiations fail, the United States may feel compelled to shift its approach away from diplomacy and toward economic leverage. In this game of foreign policy poker, Turkey’s struggling economy may force President Recep Tayyip Erdogan to fold first.

The United States and Turkey have collected long lists of grievances against each other over the last few years. On one side, the Turkish government feels that the United States has failed to take seriously its security challenges. It has been frustrated with U.S. support for a faction of Syrian Kurds (People’s Protection Units, YPG) in the fight against the Islamic State (ISIS). Given the group’s links to a domestic Kurdish terrorist organization (Kurdistan Workers’ Party, PKK), Ankara’s primary goal in Syria has been preventing the YPG from creating an autonomous Kurdish region along the Turkish border, which it fears could lead to an independence bid or be used to stage attacks on Turkey. Ankara pressed the point by launching military action against YPG forces in January 2018, which diverted some fighters away from U.S.-led operations against remaining ISIS elements.

Many Turks remain hurt by the perceived failure of Western leaders to comprehend the trauma of the July 2016 coup attempt and to express immediate support for the country’s democratically elected leader. Despite opposition to Erdogan within the electorate, there was rare consensus across the political spectrum that a military overthrow was not the solution. There is further consternation that the accused mastermind, Islamic cleric Fethullah Gulen, is residing legally in Pennsylvania. Ankara has provided boxes of documents to the U.S. Justice Department in an attempt to prove his guilt. Washington has not found the evidence sufficiently compelling to persuade a federal judge of probable cause meriting extradition. In an effort to address this impasse, U.S. officials have held several technical meetings with their Turkish counterparts to discuss the evidence presented. They have also continued separate investigations, which predate the coup, into U.S.-based charter schools run by Gulen’s followers.

For its part, the United States has begun questioning whether Turkey is still a reliable ally. Americans are troubled by the Turkish government’s overzealous response to the attempted putsch: initial efforts to detain suspected coup plotters turned into a maximalist purge of affiliated Gulenists and a witch-hunt against political opponents. A three-month state of emergency was imposed immediately following the coup, extended repeatedly, and only allowed to lapse in mid-July when parliament introduced anti-terrorism legislation that enshrines many emergency measures in Turkish law. Fluid definitions of terrorism under the state of emergency led to the imprisonment of several American citizens, as well as Turkish employees of two U.S. consulates, on baseless charges of links to the PKK and Gulen. Brunson’s case has provoked the loudest outcry in the United States and received high-level attention across the government. Turkish officials insist that the case is solely within the competence of the independent judiciary, but Erdogan’s remarks have suggested otherwise. He has engaged in hostage diplomacy, stating publicly last September that he would hand over one cleric in exchange for another: Brunson for Gulen.

The United States is also concerned about Ankara’s plans to purchase the S-400 missile defense system from Russia. This system would not be interoperable with NATO and could compromise the security of F-35 stealth fighter jets, which the United States is selling to Turkey as part of a European consortium. These plans have raised broader questions about whether Turkey is shifting its strategic orientation away from the alliance.

Too Little Too Late

When Trump took office, Erdogan hoped he would rectify Obama-era grievances by taking steps such as extraditing Gulen and ceasing cooperation with the YPG. However, the new administration did not deviate significantly from existing U.S. policies on Turkey. (This is notwithstanding the improprieties of Michael Flynn, former Trump campaign adviser and briefly U.S. national security adviser, who was allegedly offered $15 million by representatives of the Turkish government to return Gulen to Turkey, among other favors.)

Tensions spiked in the fall of 2017 when, in response to the arrests of its local staff, the U.S. embassy suspended non-immigrant visa services. Turkey promptly took reciprocal action. The United States lifted the suspension after Ankara assured it that no additional local employees were under investigation, staff would not be arrested for performing official duties, and advance notice would be given before any future arrests. But Ankara failed to release the jailed employees and even placed a third staffer under house arrest. The bilateral relationship faced additional strain in January 2018, when the Turkish military drove Russian-backed YPG fighters from the Afrin region of northwestern Syria. Ankara’s threats to expand this operation 60 miles east to Manbij, where U.S.-backed YPG fighters and U.S. Special Forces were based, raised the worrying prospect of Turkish and American soldiers pointing guns at one another.

The Trump administration has sought to improve relations through diplomatic engagement. During the same week in February 2018, the national security adviser, secretary of defense, and secretary of state all met with their Turkish counterparts. A lengthy conversation between former Secretary of State Rex Tillerson and Erdogan in Ankara led to the creation of several working groups to resolve bilateral irritants. One group has been quietly discussing judicial issues, including American political prisoners. It was later announced that prior to Tillerson’s visit the U.S. attorney’s office had dropped charges due to insufficient evidence against 11 of 15 presidential bodyguards indicted after brawling with protesters during Erdogan’s May 2017 visit to Washington.

Another group has focused on military issues. In order to dissuade Ankara from purchasing Russian S-400s, the Trump administration has improved the long-standing offer to sell Turkey the U.S.-made Patriot missile defense system by addressing the Turkish desire for more technology transfer and co-production capabilities. The two sides also developed a road map to address the continued presence of YPG forces in Manbij, Syria, which violated an Obama Administration promise that they would withdraw after eliminating ISIS fighters. Although Tillerson’s firing caused delays, his successor Mike Pompeo has continued these efforts.

In keeping with his admiration for strongmen leaders, Trump has refrained from criticizing Turkey’s democratic backsliding or imprisonment of its own citizens on dubious charges. He called Erdogan to congratulate him on winning a controversial constitutional referendum in April 2017 that created a highly centralized presidential system, and again to congratulate him on his re-election as president in June 2018. The one exception to Trump’s silence on rule of law issues has been the case of Andrew Brunson, which he and Vice President Mike Pence have raised repeatedly. Their advocacy seems driven in large part by the outcry of Christian evangelicals in the Republican base, as well as Pence’s shared Christian faith. Trump administration officials stress they are also working to resolve the cases of wrongfully imprisoned dual nationals and the Turkish employees of the consulates.

In the U.S. Congress, a growing litany of grievances against Turkey has heightened calls for punitive actions. Some members of Congress have introduced measures targeting the Turkish economy, Erdogan’s greatest domestic vulnerability. But they have also exercised strategic patience, deferring to diplomatic solutions and playing bad cop alongside the Trump administration’s outreach. For example, Senators Jeanne Shaheen and James Paul Lankford co-sponsored visa bans on Turkish officials responsible for unlawfully detaining U.S. citizens. In March, the senators dropped the sanctions when the administration requested that they allow time for Tillerson’s new diplomatic effort. On June 29, Senators Shaheen and Lindsey Graham visited Turkey and told Erdogan directly their concerns and the consequences for failing to address them. Two weeks later, when Brunson remained imprisoned after a scheduled court hearing, a bipartisan group of senators introduced a bill that would restrict loans from international financial institutions to Turkey until it releases U.S. citizens. In addition, concerns about the S-400 purchase prompted the inclusion of a provision in the National Defense Authorization bill that creates a way for the administration to remove Turkey from the F-35 consortium and potentially to block the transfer of the aircraft.

When the Turkish government moved Brunson to house arrest on July 25, Washington viewed the gesture as too little too late. The next day, the Senate Foreign Relations Committee passed the bill on loan restrictions, while Trump and Pence issued tweets calling for sanctions. Additional flashpoints are looming. Implementation of the Manbij road map is still in the honeymoon phase, and challenging negotiations on governance and security arrangements lie ahead. If Turkey does purchase the S-400s, it could be liable to existing sanctions under the Countering America's Adversaries Through Sanctions Act (CAATSA) that prohibit transactions with Russian defense entities and possible removal from the F-35 program. Pending actions by the Treasury Department could further hurt the Turkish economy. For example, Treasury may decide to fine state-owned Halkbank for fraud and conspiracy to violate Obama-era Iran sanctions, and impose new sanctions on countries that do not cease all imports of Iranian oil (which is difficult for Turkey given the lack of alternative suppliers).

Erdogan’s Weak Hand

Where do bilateral relations go from here? If Washington fails to reach a negotiated agreement with Ankara on the political prisoners, it will feel compelled to assume a tougher stance. At the same time, Turkey’s strategic geography, NATO membership, and centrality to several U.S. regional objectives make the relationship one worth preserving. As Russia and other U.S. rivals benefit from the rift with Turkey, it is ultimately not in the interest of the United States to turn away from its challenging ally. Any policy response to the current diplomatic crises should take care to prioritize the longer-term potential of the relationship.

The United States can take a page from Germany’s playbook; Germany experienced a similarly strained relationship with Turkey in recent years. Erdogan accused German authorities of “Nazi practices” after they blocked Turkish ministers from holding rallies targeting diaspora voters during the referendum campaign. The Turkish government refused to allow a Bundestag delegation to visit troops at a Turkish air base. It also arrested several German citizens on baseless charges. Berlin responded by implementing policies with economic costs while preserving lines of communication with Ankara, a strategy that has proved successful so far. It updated its travel advice to warn German nationals of the risk of arbitrary detention and its limited capacity to help; announced a review of German state guarantees for financing exports to Turkey and said it could no longer guarantee German corporate exports; and withdrew its support for near-term upgrade of the EU-Turkey customs union. Following Turkey’s release of German political prisoners earlier this year (including journalist Deniz Yucel) and its recent decision to lift the state of emergency, Berlin announced that it was relaxing its travel advice and lifting sanctions.

Russia, too, has achieved results in its relationship with Turkey using economic measures. After the Turkish military shot down a Russian jet that violated its airspace in November 2015, Moscow issued sanctions and travel restrictions that ultimately led to an apology from Erdogan the following summer.

The Turkish economy is even more vulnerable to external shocks now than it was then, making it an important potential leverage point for the United States. In early July, inflation reached 15 percent, a nearly 15-year high. The Turkish lira has lost a third of its value against the dollar since the start of emergency rule in July 2016 and dropped 20 percent since the beginning of this year. Foreign policy developments have caused further fluctuations. The Turkish economy has been sustained by cheap credit, which increases consumption and government spending. Many big holding companies are on the verge of bankruptcy, while banks would suffer from a series of defaults. There are structural weaknesses, including a current accounts deficit, external debt stock, and growing unemployment (averaging 11 percent, with youth unemployment at 25 percent). The unpredictable political environment—including deteriorating rule of law, weakened due process, and limited judicial independence—has scared off investors. The president’s new cabinet, which rewards loyalty over knowledge amid efforts to centralize power, lacks financial expertise, as evidenced by Erdogan’s appointment of his son-in-law to manage the economic portfolio.

Given Turkey’s serious economic challenges, Erdogan has overplayed a weak hand with the United States. The American government has been quietly sitting on a straight flush amid a year of painstaking efforts to improve relations, offering diplomatic carrots rather than economic sticks. The movement of Brunson to house arrest, a half measure seemingly intended to appease the U.S. without upsetting his own base, was Erdogan’s attempt to make Washington fold. Trump’s tweets threatening sanctions signal his intent to double down on his own hand, backed by congressional support for strong measures. Both the Trump administration and Congress have exhausted their strategic patience; they are now postured to change their approach and take steps intended to inflict economic pain on a NATO ally of 66 years. There is still time for a diplomatic solution if both sides return to quiet talks rather than angry rhetoric. If not, there is a real risk of ruptured relations, which could have a devastating effect on the Turkish economy, complicate the pursuit of U.S. objectives in the region, and embolden those who do not want to see Turkey facing west.