There's nothing more relaxingly unimaginative than a biopic of a socially significant artist, and 2015 didn't produce one of those more defiantly unchallenging than Trumbo. We cannot say that this life and times of Communist screenwriter Dalton Trumbo (Bryan Cranston), one of the most prominent faces to be screwed over by the anti-Leftist blacklist of Hollywood in the 1950s, is unyielding in its truthfulness and accuracy; if nothing else, fellow blacklisted writer Arlen Hird (Louis C.K.) is a composite figure of several characters, among various small-scale "print the legend!" impulses in John McNamara's screenplay. But it's a movie you badly wish to be scrupulously factual in every way, because that's the only excuse for it being so profoundly inert.

Trumbo, for those of you who aren't the most steadfast students of midcentury cultural history, was part of the Hollywood Ten, the first group of witnesses cited with contempt of Congress for refusing to play ball with the House Un-American Activities Committee in 1947; as arguably the most prestigious of the lot, he was perhaps loudest in his protestations, and had the easiest time finding paths to moonlight as a writer for low-budget schlock while working under other names (Trumbo is distinguished among all blacklisted artists for having his work win two Oscars during his time in "exile"). Trumbo wants to pay homage to the steadfastness of his belief, to the craftiness of his solution, to the madness of Hollywood then and always, and it ends up being a generally exhausting and unpleasant whirlwind tour of all kinds of stuff.

In the hands of director Jay Roach, til now almost exclusively experienced in comedies (he's the mind behind Austin Powers: International Man of Mystery and its sequels, and I think we can reasonably concur that the same film was his career high point), this is among other things an incoherent mess of tones. Louis C.K. is all ashen po-faced seriousness in a film where Michael Stuhlbarg plays a lightly silly gloss on Edward G. Robinson as a kind of dog whistle for all the Classical Hollywood cinephiles in the house (which, to be fair, is all the audience for a film about Dalton Trumbo); where John Goodman ably plays a terribly misconceived idea of exploitation producer Frank King, in a remake of Ed Wood that we didn't know we wanted, and turned out not to want; where Helen Mirren flies in from the surface of Mars to play right-wing gossip columnist Hedda Hopper as a mustache-twirling villain from a 19th Century melodrama.

The glue that would be holding all of this together if it wasn't flying apart at the seams is Cranston, effectively playing a character who was a bit of a self-conscious cartoon in real life as a collection of burly tics and intense passions. Nothing can actually redeem some of the lowest registers of the plot-by-numbers script (I assume Cranston's Oscar nomination was in recognition of not dying of shame when he's obliged to explain Communism to his daughter during a scene lit and staged like an ad for chlamydia medication), but at least the actor's sense of big-throated jolliness throughout helps make some of the more flatly mediocre passages pass by without much fuss.