How times have changed in American politics. A bit over half a century ago, it was conventional wisdom that a divorced man couldn’t be elected president. Then it was assumed that an adulterer was unelectable. Reagan and Clinton, in order, shattered those ideas, and now a twice-divorced fellow who’s boasted publicly of being a serial adulterer and sexual harasser—while also denying it, of course—holds the Oval Office. It certainly represents a sea change in attitude among voters.

Jason Reitman’s “The Front Runner” is about what in retrospect was a major episode in that shift—as well as one showing the morphing of American political journalism in the direction of crass tabloidism: the abbreviated 1988 presidential campaign of Colorado Senator Gary Hart. Based on a book by Matt Bai, as adapted by him, Jay Carson and Reitman, it shows how a politician who seemed to have a clear path to the presidential nomination of one of the two major parties was forced to pull out of the race after only three weeks because a team of newspapermen decided to stake out his house to collect evidence of adulterous behavior and then published the result, creating a firestorm despite the fact that their reporting was, at best, imperfect.

Reitman begins with a prologue recalling Hart’s unsuccessful presidential run in 1984, when Walter Mondale, the eventual Democratic nominee, eviscerated the boyish lawmaker by asking of his hazy policy suggestions—after a Wendy’s commercial popular at the time—“Where’s the beef?” Four years later, Mondale was back in Minnesota, Reagan remained in the White House, and Hart was riding high in the polls. As played by Hugh Jackman, he’s handsome, articulate and athletic (a bit too much so, in fact—Hart was actually more professorial and wonky); he also a strong-minded, confident wife (Vera Farmiga), and a dedicated campaign manager (J.K. Simmons) presiding over an enthusiastic staff, many of them idealistic young volunteers.

Hart pretty obviously cultivated a Kennedy-esque persona, and unhappily that proved to extend to an attitude toward marital fidelity that was not exactly in tune with middle American values, though it certainly wasn’t unlike that of many previous presidents. The difference was that in 1988, after the messes of Vietnam and Watergate, questions of character loomed larger in assessments of candidates, and what reporters looking for dirt considered appropriate subjects for investigation expanded to include their private lives—something that had been considered largely off-limits in recent times, though eruptions of scandals sometimes became headline news.

That was the backdrop against which the staff of the Miami Herald reacted when an anonymous source (later identified as a woman named Donna Weems) reported that a friend of hers—Donna Rice (Sara Paxton—was having an affair with Hart. Several reporters, including Tom Fiedler (Steve Zissis] and one who here goes by the name of Pete Murphy (Bill Burr), apparently a pseudonym—were assigned to check on the report, and confirmed via their Washington stakeout that Rice did indeed visit Hart; the even accosted the senator outside his Washington townhouse and pressed their editor—another apparent composite called Bob Martindale (Kevin Pollak)—to publish the story.

The explosion of bad publicity was immediate, and Hart, pleading privacy rights, was unable to handle it effectively. His campaign imploding, he withdrew so as not to be, as he put it, a distraction, though what the film doesn’t add was that he later reentered the race, only to do poorly in the primaries.

Reitman’s film gives a decent overview of the aborted Hart campaign, though its point of view is pretty narrow and the overall treatment rather superficial. He and Jackman paint a reasonably truthful external portrait of Hart, even if they never dig very deeply into his character, tending to let him off rather easy; and the other figures associated with him are depicted in pretty one-dimensional terms (Simmons’ manager in particular), with only Farmiga getting an opportunity to demonstrate the rage of a wife wronged by her husband’s misconduct.

The representatives of the Fourth Estate, on the other hand, are very negatively portrayed. Zissis’ Fiedler, for instance, is depicted as a sweaty, weasely sort, torn between whatever vestige of principle he might retain and the pull of his skuzzy partner Murphy, who revels in pushing the story as far as it will go. Fielder certainly gets his comeuppance in an interview with Ted Koppel, during which he squirms under questioning. (In reality he went on to a distinguished journalistic career at the Herald, later taking a deanship at Boston University.) The Herald’s editor, the pseudonymous Martindale, also gets blasted in a face-off with Hart in which he comes off looking slippery and evasive.

The film also makes much of the argument that the Herald justified its tactics by referring to an offhanded remark Hart made to another reporter to follow him if he wanted to check out rumors about him. The point, repeated several times, is that the remark hadn’t yet been published when the Herald initiated its investigation, and was taken up as a post-factum rationale for the tactics the paper adopted.

We’re also shown other newspapermen being dragged unwillingly toward the National Enquirer style of gotcha journalism (it was that paper that published the infamous photo of Hart and Rice on the yacht unfortunately called the Monkey Business, as a clip from Johnny Carson’s “Tonight” show reminds us here). That’s shown in the newsroom of the Washington Post, where editor Ben Bradlee (Alfred Molina, far softer than the portrait of him Jason Robards, Jr. drew so unforgettably in “All the President’s Men”) wistfully recalls the pass the press gave to JFK and LBJ on their womanizing and young reporter A.J. Parker (Mamoudou Athie)—another fictionalized character—wrestles with his conscience about taking on the story, though he eventually does so, earning him a scornful look from Hart.

People will debate how accurate Bai and Reitman’s account of the whole sorry business is, but after all “The Front Runner” does not pose as a documentary; and as a docu-drama, with all the caveats that category necessarily carries, it makes the points it wants to with economy and dramatic urgency, and political junkies in particular will enjoy it, if only to nitpick at its flaws. Steve Saklad’s production design and Danny Glicker’s costumes are unobtrusively correct in period terms, Eric Steelberg’s cinematography is atmospheric, and Stefan Grube’s editing is smooth, especially considering Reitman’s penchant for combining archival material with newly-shot footage. One annoyance is Rob Simonsen’s score, which, in the campaign sequences, bounces along rhythmically at inordinately loud volume.

Nobody comes out well in this sad story—neither Hart, who despite good qualities is portrayed as a man with feet of clay, nor the staff at the Miami Herald, portrayed as more interested in a sordid scoop than accuracy. Some might believe that the American people should be added to that list, since the eventual Democratic nominee was Michael Dukakis, who lost to George H.W. Bush, establishing a dynasty that led to the election of his son, to “weapons of mass destruction” and to the war in Iraq. We’ll have to wait to see what Adam McKay’s upcoming “Vice” makes of all that.

Of course, “The Front Runner” doesn’t offer a persuasive argument that things would have been appreciably better if Hart had won the Democratic nomination, and the presidency.