I think if the FAA threatened to play hard ball if Europe don't go along with an exemption to the 737Max, of all types, it would blow up right back in their faces. It would be good if someone would ask EASA right now in public what their attitude would be. I guess the FAA already have.
As another transport journalist once wrote "Statements that 'Safety is our First Priority' generally follow an event which shows that it isn't".