Turkey appears determined to counter US warnings against purchasing Russia's S-400 surface-to-air missile-defense system, despite growing threats from Washington.

If Turkish President Recep Tayyip Erdogan buys Russia's missile-defense product, Washington won't sell Ankara the F-35 jets Erdogan wants. But Ankara has two means of leverage at hand: First, it can look for an alternative to the F-35s; and second, it can scare up some hysteria by allowing a Russian naval presence on its Mediterranean coast.

Worrying reports from Washington came one right after the other following March 31 local elections in Turkey that sapped strength from Erdogan's Justice and Development Party. The Washington administration hardened its position regarding Ankara’s “done deal” narrative about buying the S-400 air defense systems from Russia, and Russia’s announcement that the systems will be delivered to Turkey in July — perhaps earlier.

The headline of an April 9 op-ed in the New York Times by four US senators succinctly summarized the rise in Washington's dominating attitude: "A U.S. Fighter Jet or a Russian Missile System. Not Both." Washington says Turkey's possession of both systems would give Russia access to US technology. The United States had offered to sell Turkey US Patriot missile systems in place of the S-400, but no deal was reached.