The Head of State is elected for a four-year term. By tradition it used to be no more than two consecutive four-year terms, now that is also in the Constitution. So no one runs the show for more than eight years. And if people are really unhappy, the President can be Impeached and removed from office (Impeachment is the process, not the result), although the removal part has never happened.
Again, the Electeds work for us, not the other way around.
U.S. Const. art II § 1; am. XX & XXII.