ANKARA, July 13 -- Recep Tayyip Erdogan has been promised F-35s. Receiving them is a more complicated matter.

A Turkish government source told RIA Novosti on Monday that Ankara's path back to the Lockheed Martin fifth-generation fighter program runs through at least two distinct pieces of American law and a mandatory 90-day Congressional review that no executive decision can shorten. The statement, issued as both governments described negotiations continuing at political and technical levels, identifies Congress, not the White House, as the decisive variable in whether Turkey actually returns to the program it was expelled from in 2019.

Political discussion around Turkey's potential reinstatement has centered on the Countering America's...