Sleek, confident and peppered with delicious portraits in pursuit, deceit and evasion, the carnival of papal intrigue known as “Conclave” works like gangbusters. It’s the best recent Agatha Christie adaptation not based on an Agatha Christie mystery, because it’s from a book by Robert Harris. I describe it that way not to mess with logic (that’s just a bonus), but to suggest something of the mechanics and payoffs at hand.

Finessed, adroitly, into screenplay form by Peter Straughan, streamlining the narrative of Harris’ 2016 bestseller, it’s a tasty election thriller with Ralph Fiennes fine-tuning his mastery of purring interrogative wiles. He plays Cardinal Lawrence, sane, tolerant and ailing, charged with managing the film’s meticulously fraught process of naming a new pope in the wake of the sudden death of the old one. The results, directed with nearly comical panache by Edward Berger, make for a very enjoyable two-hour diversion from any other elections you might find preoccupying your head-space these days.

Berger is hot off his pile-driving remake of “All Quiet on the Western Front,” a film that doesn’t suggest immediate comparisons to “Conclave.” The way he and cinematographer Stéphane Fontaine snake through the Vatican’s halls, tracking Fiennes and his confidants and adversaries, it’s as if we’re back in the Great War trenches. While Cardinal Lawrence may argue with someone referring to his conclave as a war, Stanley Tucci’s humble .