Panamanian palm - the term given to the covert handshake between a central American country and a superpower which inevitably leads to their mutual betrayal.

That's a cool one, Rubrick! And I think you may have just coined a phrase that works on an even more pervasive level, meaning an insincere handshake.

Yeah..."just give 'em the ol' Panamanian palm!"

'Course, the PC Brigade from Panama, and those of Panamanian descent, will prolly start screaming protest banners about it.