Authoritarian governments around the world have increasingly embraced the disgraceful tactic of arresting U.S. citizens and holding them as de facto hostages in an attempt to gain leverage over Washington. Iran and North Korea were pioneering practitioners – and both repeatedly extracted U.S. concessions. That probably encouraged other nations, including Egypt and Venezuela. Now comes Recep Tayyip Erdogan’s Turkey, a NATO member that appears well on its way to becoming an outlaw state.

In the past year the Erdogan government has seized a dozen Americans as well as two Turks working for U.S. consulates. Erdogan recently made clear that the prisoners are little more than pawns whom he wishes to trade for Turks in the United States.

Following the latest arrest, of a consular employee in Istanbul, an understandably exasperated U.S. Embassy announced a freeze Sunday on the issuance of nonimmigrant visas to Turks – a drastic measure that was quickly reciprocated by the Turkish mission in Washington. Such a ban could hurt many innocent people, including Turkish journalists and civil society activists working to resist Erdogan’s repression. If it endures, it should be refined to target government officials, business executives and others linked to the regime.

There’s no question, however, that the Trump administration, which has persisted in describing Erdogan as a close ally, must now stand up to his bullying. The Turkish ruler appears to believe he can persecute Americans with impunity; his arrogance was encapsulated when he watched as his security detail attacked peaceful protesters outside the Turkish ambassador’s residence in Washington in May. His demands about Turks in the United States are equally lawless.