(MANDEL NGAN/AFP via Getty Images)WASHINGTON — Four key members of Congress, either individually or collectively, have quietly frozen all major U.S. arms sales to Turkey for nearly two years in a move to pressure Ankara to abandon its air defense system, Defense News has learned.The legislative action, which has not been previously reported, is another sign of the deeply fractured relationship between the two NATO allies, a disruption that has already led to from the F-35 joint strike fighter program.While it is unclear exactly how many potential sales have been held back, at least two...…(MANDEL NGAN/AFP via Getty Images)WASHINGTON — Four key members of Congress, either individually or collectively, have quietly frozen all major U.S. arms sales to Turkey for nearly two years in a move to pressure Ankara to abandon its air defense system, Defense News has learned.The legislative action, which has not been previously reported, is another sign of the deeply fractured relationship between the two NATO allies, a disruption that has already led to from the F-35 joint strike fighter program.While it is unclear exactly how many potential sales have been held back, at least two...WW…