Intel: How the US, Turkey got into standoff over Russia’s S-400 air defense system

In a visit to the Kremlin on Monday, Turkish President Tayyip Recep Erdogan reiterated his determination to press ahead with the purchase of a Russian missile defense system that has strained ties with the United States.

“We have determined our road map for the S-400,” Erdogan said. “No one can expect us to give up on this.”