Gabriel Range is a documentary filmmaker, of whom few had heard until this week. His 2003 television production, The Day Britain Stopped, was a pioneering essay in the “fake documentary”, in which imaginary future events are synthesized in fine detail. He has now achieved fame, even before anyone has seen his new essay in that genre, Death of a President. It will premiere at the Toronto Film Festival, Sept. 10th, and then show on the British TV channel, More4. The fame, or more properly, infamy, is for his audacity in making a film about the assassination of a U.S. President...