In the world of diplomacy sometimes "obvious" facts aren't "clear" but you use nice words, i.e. one could talk to an embassador and give them the chance of introducing their representative.

I however assume the original poster was more inclined "do the, have any means to summon some American citizen" (to which the answer is "they can summon who they like, and the other can do what they like, unless his state of residence has some form of agreement (like extraditement in criminal court cases)")