US officials wonder: Did Turkish leader's coup memories drive Russia arms deal?

For some US officials, the Trump administration's failure to persuade Turkey not to buy a Russian air defense system may have its roots in a coup attempt against President Tayyip Erdogan three years ago this week.
While they recognize that worsening US relations with Turkey in recent years and Russia's growing clout with Ankara may also have helped sway Turkey toward buying the S-400 system, three US officials and a defense source told Reuters of another working theory that has gained ground within the Trump administration.
One reason Erdogan may have chosen to buy from Russia rather than from a fellow NATO member is that he might be wary of his own air force, which played a major role in the coup attempt on July 15, 2016, these officials say.
S-400 missiles, which Turkey began taking delivery of last Friday, would be better at fending off any attack on the Turkish...