This piece discusses the plot of “Miss Sloane.”

“Cynical is a word used by Pollyannas to indicate the lack of naivete they so keenly exhibit,” lobbyist Elizabeth Sloane (Jessica Chastain) says sharply midway through “Miss Sloane.” She has quit her job at a conservative firm to join the Brady Campaign’s latest push for a background-check bill, bringing much of her team with her, and the tactics that made her a legend at her old firm aren’t exactly endearing her to her new, more-liberal colleagues. Unfortunately, Sloane’s diagnosis of why gun-control efforts keep failing is also the key to why “Miss Sloane,” which has the misfortune to arrive after this presidential election, doesn’t work: It’s a naive movie that believes itself to be cynical, and as a result, misses just how deep the rot in Washington really lies.

The biggest problem with “Miss Sloane” is the lobbying campaign at the heart of it. The movie wants to be a radical look at why gun control has been so devilishly difficult to get passed, and to suggest that a new way of thinking might shake up the issue. But Sloane’s theories about how to change the debate are actually old liberal ideas that haven’t worked before.

First, she diagnoses the problem as money in politics and sets up a group of 3 million small donors who donate a collective $15 million for gun control. It’s supposed to be a way of demonstrating that there’s a constituency for the issue, but that figure is minor: the National Rifle Association’s budget in 2010 was $243.5 million. Michael Bloomberg’s Everytown for Gun Safety has begun closing the lobbying gap with the NRA.

The challenge, though, isn’t really money. As the New Yorker’s James Surowiecki writes: “The N.R.A.’s biggest asset isn’t cash but the devotion of its members. … People who were in favor of permits for gun owners described themselves as more invested in the issue than gun-rights supporters did. Yet people in the latter group were four times as likely to have donated money and written a politician about the issue.”

Sloane’s other big idea is to find a charismatic survivor of gun violence and turn her into a national advocate, as if the issue is an empathy or experiential gap. Again, experience suggests the limits of this approach. The pain suffered by families of those killed in the gun massacre at Sandy Hook Elementary School has not proved a singular force in American legislatures, either.

Though “Miss Sloane” presents both prongs of this campaign as ambitious, they reflect familiar liberal thinking about how politics works. If only the playing field were fair, and we removed money from politics, surely our ideas would win. If only voters could see the agony of people who have been hurt, they would surely respond.

Both of these convictions rest on the belief that liberal ideas are inherently more appealing if only they could get a hearing, and that in politics, we ought to give deference to people who have been wronged. The problem is that sometimes, people hear liberal ideas and reject them. And as election and legislative fights show over and over again, Americans are often willing to tally up others’ pain as the price we pay for things such as the right to buy any guns we want, as quickly as we want them. Like the idea that demography will deliver a permanent Democratic majority, these are wishes, not hard-nosed assessments. It makes “Miss Sloane” look silly to sell them as such.

The other arena for the supposed cynicism of “Miss Sloane” is a congressional investigation into Sloane’s lobbying work, conducted by congressman Ron Sperling (John Lithgow) that’s full of puzzling moments.

Sperling goes after Sloane on the grounds that she illegally facilitated a congressman’s overseas trip. At a moment when the president-elect of the United States is poised to profit from his own Secret Service protection and foreign dignitaries are lining up reservations at the Trump Hotel in Washington, hoping to ingratiate themselves with the future leader of the free world, the idea that Congress would get hysterical over this sort of minor violation (or that a congressman’s obvious attempts to manipulate this particular molehill into a mountain would attract major press attention) seems almost sweetly nostalgic for a more innocent, less rampantly corrupt period in our history.

And “Miss Sloane” never engages with the fact that to nail this lobbyist, Sperling is hanging another member of Congress out to dry. (He is also exposing Sloane’s old firm, which is working with him, in another bit of movie illogic.) It would be one thing if the movie had a reason that Sperling was willing to expose his colleague to corruption charges and embarrassment. Instead, the movie seems vaguely unaware of congressional clubbiness, a force that is not inherently corrupting but certainly exerts an influence in Washington.

The behavior of Sloane herself is no more explicable or illuminating. Though she begins the movie by lecturing us that “lobbying is about foresight, about anticipating your opponents’ moves and devising countermeasures. … It’s about making sure you surprise them and they don’t surprise you,” Sloane appears utterly shocked when Sperling brings up compromising details from her personal life. We see her throw strategic tantrums at certain moments in the film, but at least one of the twists in the hearing appears to come as a surprise to her, undercutting her reputation as a tactical genius. From an argumentative perspective, this is puzzling. From a storytelling perspective, at least one of Sperling’s attempts to expose Sloane hits such a weird dead end that the plot point it’s based on ought to have been cut from the movie entirely.

“I care about the ends,” Sloane declares smugly at one point, delivering one more supposed proof of why her cynicism makes her a better lobbyist. “You liberals can care about the means.” That’s a cliche anyway, and it’s even more frustrating when “Miss Sloane” is so thoroughly and consistently wrong about the dark arts of politics.