One of McKay’s models was “The Power Broker,” Robert Caro’s landmark biography of Robert Moses. “He’s in the middle of all this stuff,” McKay said of Cheney, “and finally he gets his hand on the wheel.” Unlike Caro, McKay had to tell his story through a camera, and so there are compressions, elisions and metaphors in “Vice” that reflect both a filmmaker’s desire to enthrall the crowd and a prosecutor’s desire to nail the defendant. Reading journalistic accounts of Cheney’s move, in 2000, from the private sector back into public service, we learn that he took elaborate steps to divest from Halliburton, the oil conglomerate where he was C.E.O., to avoid the appearance of conflict; here, the relationship between Cheney and the energy sector is presented as one of clear cronyism. Or take Sept. 11. In Barton Gellman’s play-by-play of that morning in “Angler,” it’s strongly implied that Cheney usurped Bush’s authority, ignoring the chain of command and giving fighter jets the O.K. to shoot down commercial airliners if they appeared to be hijacked. The official White House version was that Bush gave Cheney permission to pass along this order, and Gellman, poring carefully through communications records and notes taken by administration staff members, leaves open the extremely slim possibility that this is true. In “Vice” there is no such equivocation. We see Cheney give the order to take out the planes himself. Compression, of course, isn’t the same as distortion: Jane Mayer, the investigative journalist, described this scene to me as “a perfect gem,” and told McKay, after he screened the movie for her, that he “got it right.”

One way McKay might have buttressed “Vice” against possible charges of liberal bias would be to include the sorts of political critiques he readily offers up in conversation. “When Clinton was elected, he cut welfare and deregulated banks, just like a Republican would have done,” he said, from his couch. “Obama waged a war against whistle-blowers, he let the banks off the hook and he expanded executive power.” McKay did tinker for a while with stitching points like these into “Vice” — making it “the story of Dick Cheney and the rise of the Republican Party, and how they got so big they swallowed the Democrats.” To this end, he pieced in footage of Hillary Clinton supporting the Iraq war. “But it’s hard,” McKay went on. “The audience only has a certain amount of oxygen in their lungs.” As he said earlier: “I could have made the movie three and a half hours long, but you can thank me that I didn’t.” (The film runs just over 130 minutes.)

McKay predicted that some of the fiercest criticisms of “Vice” might come from putatively sympathetic voices: “I actually think left-wing friends of mine are going to be mad at me for humanizing him as much as I do.” Throughout the film, Cheney is depicted as a fearsomely capable stalker of prey; a recurring motif concerns his passion for fly fishing, which McKay described to me as crucial to understanding him. He hired a fly fisherman as a consultant. “You can’t believe the level of patience and detail that’s involved — lifting up the rocks to see what kinds of bugs are underneath so you know what kind of lure to use; watching the drift, the way the sun’s hitting it so you know what illusion to create with your lure. And that’s the story with Dick Cheney. Meticulous detail and tremendous patience.” Cheney is rendered tenderly in his interactions with Lynne, his sweetheart since high school, and with his second daughter, Mary, whose coming out as gay in the mid-’80s he met with private encouragement and affection. Christian Bale told me that he seized on Cheney’s marriage as his way into the role. “With any part, you choose what you focus on,” he said, explaining that, in “Vice,” he chose “the love story. I think Cheney’s one of the most romantic men around. At the start he wasn’t particularly ambitious. Very laid back. But he has this undying love, where he’ll do anything to win Lynne’s approval — he did it all for her.” He added that “the hardest thing with playing him was trying to understand that awesome power. I could never quite imagine what it must be like to wake up every morning knowing the power within your hands, where your choices affect whether people will die. I obsessed over it for months. But I don’t think he sees himself as a villain — unless someone’s a sociopath, I think they believe their motives are for a bigger good.”

On the subject of villainy, McKay said: “Cheney and Bush did kill, conservatively, half a million civilians in Iraq. Some estimates have it at more than a million. So he’s pretty bad.” But, he said, “I think you have to humanize him, because unless we see how a regular human being can go down these roads, it’s useless.” (McKay has heard nothing from the Cheneys, who did not participate in the making of the film, although he noted that Mary started following him on Twitter.)

Recently, a sizable portion of the left has adopted surprising, relatively sanguine attitudes toward the Bush-Cheney years. I asked McKay, who directed a scathingly satirical 2009 Broadway show about Bush called, “You’re Welcome America,” whether he saw his unsparing portrait of Cheney in “Vice” — humanizing gestures notwithstanding — as a would-be corrective to liberal amnesia on this score. “I hope to God that it is,” McKay said, nodding. “Really what that shows you is the number of people for whom government is just about appearance. Bush and Cheney just kept up the facade, whereas this administration doesn’t even remotely pretend. So when I hear people say, ‘I miss the days of Bush and Cheney,’ what they’re really saying is, ‘I miss the days when people would at least pretend.’ ” He went on: “Every time I see it, I shake my head, like, ‘You’ve got to be kidding me. The world economy collapsed, we had the greatest military fiasco in U.S. history apart from Vietnam.’ When I hear ‘Trump makes you miss Bush,’ I go, ‘There’s no question that Bush and Cheney are way ahead of him in terms of damage done.’ ” He characterized such Bush nostalgia bluntly: “Now that my house is on fire, I long for when it was infested by bees.”

In July, McKay was sprawled in a similarly oblong configuration across a different couch, this one in a postproduction suite on the Sony Pictures lot. He was working with the editor Hank Corwin to fine-tune “Vice” for release. Corwin, a Hollywood veteran who cut “The Big Short” and whose other credits include Terrence Malick’s “Tree of Life” and Oliver Stone’s “Natural Born Killers,” stood at a monitor in beat-up running sneakers. An executive producer, Robyn Wholey, sat on a stool.

“We’ve been playing with this one scene,” McKay explained. “It’s one of our most challenging runs.” The scene in question takes place in Dick and Lynne Cheney’s bedroom on a stormy night in 2000, after George W. Bush has won the Republican nomination and offered Cheney the No. 2 spot on the ticket. Cheney has declined, volunteering instead to lead the vice-presidential search. In the available accounts of this moment, Cheney’s motivations remain obscure. Was the search a canard — a mechanism for Cheney, who always intended to take the job, to amass dirt on G.O.P. luminaries that he could later leverage against them? By stalling, was he able to extract more power from Bush when he eventually said yes?