Turkish President Recep Tayyip Erdogan may be playing dumb, but he's not stupid.
The strongman plunked down a deposit for Russia's advanced S-400 air-defense system in December 2017—months after Congress passed a law that triggers painful U.S. sanctions on governments that purchase Russian armaments. Now Mr. Erdogan wants an exemption, and he apparently believes President Trump is inclined to give him one. Mr. Trump likely cannot do so without congressional approval. But even if he could, he shouldn't.
The Countering America's Adversaries Through Sanctions Act, or CAATSA, is crystal clear about imposing sanctions on any entity that "engages in a significant transaction with . . . defense or intelligence sectors of the Government of the Russian Federation." The S-400 cost Ankara around $2.5 billion and is widely believed to rank among the most lethal air defense systems in the world.
But its lethality is not the reason that the U.S. State and Treasury departments have been pleading with Mr. Erdogan to cancel the sale. The greater problem is that it risks exposing U.S. technology to hostile powers.
Turkey is in line to receive the American-made F-35; Turkish pilots are already training on these fifth-generation fighter aircraft at a base in Arizona. Operating the aircraft in conjunction with Russian S-400s could enable Moscow to track and collect intelligence on the capabilities of the most advanced jet fighter in the world. This would threaten the U.S. military's already diminishing qualitative advantage—not to mention that of American allies who also acquire the aircraft.
In addition to inviting congressionally mandated sanctions, Mr. Erdogan's decision to acquire the S-400 could cost him the F-35. The Pentagon officially halted the delivery of F-35 training equipment and related material on April 1. Turkish pilots are still training, but it's unclear how much longer that will last.
Some argue that these measures against Turkey are a mistake. After all, Turkey is a member of the North Atlantic Treaty Organization. And if the U.S. is not careful, it could push Ankara out of the alliance—straight into the arms of Russia or even Iran.
Yet Turkey has been outside the NATO tent for a decade now. It is the largest external headquarters for the terrorist group Hamas in the Middle East. It has supported the worst jihadist actors in the Syrian civil war, including some linked to al Qaeda and Islamic State. From 2012-15, at the height of the effort to force Iran to relinquish its nuclear ambitions, the Turks were involved in a massive sanctions evasion scheme that netted Iran an estimated $20 billion.
Meanwhile, Turkey has descended into authoritarianism domestically. The government in Ankara is now the world's top jailer of journalists. It has held Americans and other Westerners hostage. Mr. Erdogan has a personal stranglehold on the media and the judiciary. Whatever is left of the country's democratic process is groaning under the weight of Mr. Erdogan's efforts to manipulate it—as he demonstrated by his government's recent nullification of the March 31 Istanbul mayoral election.
American officials and legislators have demonstrated great patience despite all this. They have repeatedly engaged the Turks and forestalled punitive measures in hopes of a turnaround. Sadly, U.S. efforts to maintain the alliance with Turkey may have succeeded only in convincing Ankara that it is "too big to fail." Turkish officials have become convinced that the U.S. will blink first.
Specifically, they think Mr. Trump will. As one Turkish official remarked in April, "We are getting signals that Trump pursues a more positive attitude than Congress."
This would not be the first time an anti-American strongman has sought to drive a wedge between the president and Congress to get what he wants. Russia is now infamous for doing this in the wake of the 2016 U.S. elections. That's one reason Congress passed CAATSA in 2017.
Mr. Trump lambastes allies who fail to pull their weight. Turkey tops that list, relying on U.S. beneficence while undermining U.S. interests. The president should not succumb to Mr. Erdogan's blandishments. Instead of coddling Mr. Erdogan, the administration must force Turkey to decide whether it remains a part of the Western alliance in fact or in name only.
Mr. Edelman, a former U.S. ambassador to Turkey, is chairman of the Turkey program at Foundation for Defense of Democracies. Mr. Schanzer, a former terrorism finance analyst at the U.S. Treasury, is senior vice president for research at FDD.