Though Douglas Adams was describing Zaphod Beeblebrox, Galactic President, in his The Hitchhikers Guide to the Galaxy, the author anticipated a time beyond his own lifespan— our own:
The President in particular is very much a figurehead — he wields no real power whatsoever. He is apparently chosen by the government, but the qualities he is required to display are not those of leadership but those of finely judged outrage. For this reason the President is always a controversial choice, always an infuriating but fascinating character. His job is not to wield power but to draw attention away from it.
Adams’ quote above might be amended as to the president’s powerlessness, in present circumstances. He has no positive power, and can only gnaw away at the foundations of government, but can add nothing at all, the way a termite can eat wood, yet cannot make wood.
But where best to locate the Beeblebrox Equivalent? The UK or the US? Beeblebrox sported two heads, so the answer ‘both’ is reasonable.