(Bloomberg Opinion) -- It’s time for NATO to call Turkey’s bluff. President Recep Tayyip Erdogan said once again last week that his controversial plan to purchase a Russian missile-defense system is a “done deal” — even though the U.S. had warned that this could give Russia access to NATO’s air-defense secrets. 

Amid an escalating war of words, this threat shouldn’t be minimized. Russia’s system, the S-400, could shoot down NATO fighter jets, and Moscow’s engineers are expected to help Turkey run it once the purchase is completed. That might give Russia insight into sensitive U.S. technology — especially that used by the F-35 stealth fighter, which Turkey is helping to build.

In addition to being dangerous, the decision is entirely self-defeating. The U.S. has suspended deliveries of F-35 equipment to Turkey, even though Turkish companies were set to produce about $12 billion in parts for the jet and the Turkish air force planned to buy about 100 of them. It has also rebuffed a generous U.S. offer of comparable Patriot missiles that could’ve avoided the whole mess.

That Erdogan entertained a Russian offer at all was less about security than his perception that Turkey relies too heavily on Western military and economic support, a frustration that has grown with American and European criticism of his increasingly autocratic rule. Unique among NATO leaders, Erdogan has indulged in bellicose anti-Western rhetoric, even accusing allied countries of trying to topple his government. He apparently thinks the alliance won’t punish his repeated demonstrations of bad faith because Turkey has historically been important in countering NATO’s biggest security concerns, Russian expansionism and Islamic terrorism.

But his sense of Turkey’s centrality is inflated. Far from being a bulwark against Russia, it has only deepened its economic and security ties to Moscow under Erdogan’s leadership. Its contribution to the fight against terrorism has never extended beyond calculations of its own interest.

Now NATO must demonstrate that the collective security of its alliance is more important than the narrow calculations of a single member. Turkey should be barred from the F-35 manufacturing program — other members would be glad to pick up its share — and from purchasing the aircraft. Donald Trump’s administration should also impose sanctions, as it did last year when China bought Russian jets and missile systems.

If Erdogan goes ahead regardless, the alliance should be prepared to scale down Turkey’s role in any joint military activity. If necessary, the U.S. could follow Germany’s example and withdraw from Incirlik Air Base; Jordan’s Muwaffaq Salti Air Base is one of several feasible alternatives.

For his part, Erdogan should recognize that NATO membership has well served Turkey’s military, political and economic interests for nearly seven decades. Despite his rhetoric, it can’t have escaped him that the alternative to the alliance is a growing dependence on Russia — hardly a desirable outcome for a leader who prizes geopolitical autonomy.

Membership of the Western alliance is by far the better option for Turkey. But it requires respecting the group’s collective concerns. Erdogan needs to show that he does.

—Editors: Bobby Ghosh, Timothy Lavin.

To contact the senior editor responsible for Bloomberg Opinion’s editorials: David Shipley at davidshipley@bloomberg.net, .

Editorials are written by the Bloomberg Opinion editorial board.

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