One of the most difficult movie scenes must be fake documentary footage. Real is hard to do. We believe in Leonardo DiCaprio rescuing oppressed diamonds out of Africa because of our suspended disbelief, not because it really looks real. “Real” looks dodgy — stiffer or looser than fiction is comfortable with. “Real” looks like “Frontline,” exactly what “Death of a President” aspires to be — concocted TV journalism recounting the assassination of President George W. Bush and its aftermath. In look and feel, it is an uncanny success, and it even tries to answer the question Bush himself might ask if he saw it: “Why me?”

“Death of a President” tries not to reveal its prejudices in the process. “Dick Cheney as president?!” it screams. No, not really. The jabs are subtle. Bush’s speechwriter mistakenly refers to North Korea’s dictator as Kim Il Jung. In another scene, a law enforcement honcho muses, “I think there’s a new type of anarchist, one that thinks that anything goes.” Which anarchists is he talking about — ones who fire protest chants or ones who fire U.S. attorneys? The movie clearly has an agenda about the questions it raises.

Here’s another one, posited by a forensic scientist who disagrees that a suspected Syrian immigrant is the culprit: “They seem to be working backwards in this case,” he says. “They had a hypothesis of guilt, and they tried to fit the evidence to prove that.” In cases like this, subtlety goes right out the window.

Actors like the forensic scientist are as believable as any real person. Others have more trouble holding their note, but “Death” is especially good at action sequences. As some of the bonus interviews reveal, some of the sequences aren’t fake at all. Too much information? Maybe, especially the revelation about the protest scenes. Evidently the film crew found a real protest to use for footage, but began filming only after planting fake demonstrators with fake placards that showed up better on camera. “Death of a President” is technically brilliant, but that’s just too postmodern to stomach. (R)***