For over a year now, political commentators have struggled to identify Donald Trump's past political counterpart. Is he like Barry Goldwater, a dangerous extremist seizing control from the party establishment? Or George Wallace, a racist demagogue playing off his supporters' fear and bigotry? Is he a European-style far-right populist like Pim Fortuyn, or is he more like Italy's former billionaire leader Silvio Berlusconi? And, naturally, there have been the inevitable Hitler/Mussolini comparisons.

But historians of 1970s American politics say Trump's recent encouragement of and tolerance for violence against demonstrators brings to mind not a past candidate but a past president: Richard Nixon.

Much of what Trump is doing in this regard Nixon did first. And Trump is starting to actively embrace Nixonian rhetoric, calling for "law and order" in the wake of the shooting of police officers in Baton Rouge. Trump advisor Paul Manafort told reporters that Trump extensively studied Nixon's 1968 convention speech in crafting his own.

But it's not just that. Referring specifically to Trump's relationship with protesters, Elizabeth Drew, a veteran journalist and author of Washington Journal: Reporting Watergate and Richard Nixon's Downfall, says, "There's an absolute parallel, an eerie parallel, between what Trump is doing and what Nixon did."

"The similarity is that they seem to not have any qualms, any sense of shame at using power to get back at people that they feel were unkind or unfair to them," NYU professor and former Nixon Library director Tim Naftali adds.

Nixon rabble-roused against demonstrators, like Trump. After New York construction worker union members violently attacked Vietnam protesters, Nixon supported them, even accepting a symbolic hard hat from their leader. In 1969, then-Deputy Attorney General Richard Kleindienst mused to Drew, on the record, about opening "detention camps" for antiwar protesters. In 1970 Nixon personally approved a plan for burglary and illegal surveillance targeting protesters.

All these things seem of a piece with the kind of vengeful targeting of protesters that Trump seems to relish. "At times Trump acts publicly the way Nixon acted privately, as we know him from the [White House] tapes," Naftali says.

Nixon presaged Trump's hatred for the press

Donald Trump has staked out a remarkably hostile position regarding journalists throughout this campaign. As early as August, he had security forcibly eject Univision reporter Jorge Ramos from a press conference. At a November event in South Carolina, he mocked and pantomimed New York Times reporter Serge Kovaleski's disability. In January, he kicked New York Times reporter Trip Gabriel out of an event for having written an article critical of Trump's Iowa campaign. Trump campaign manager Corey Lewandowski allegedly assaulted Breitbart reporter Michelle Fields at a rally.

When Trump has assailed the press at events, his followers have sometimes taken the opportunity to personally jeer them:

Trump trashes press. Crowd jeers. Guy by press 'pen' looks at us & screams "you're a bitch!" Other gentleman gives cameras the double bird. — Katy Tur (@KatyTurNBC) February 21, 2016

"Sometimes, he gets personal with the press," Slate's Seth Stevenson reports. "At one rally, Trump referred to NBC News reporter Katy Tur as 'little Katy, third-rate journalist' while she was in the pen, surrounded by his riled-up groupies."

"Trump has denounced the media as 'illegitimate,' 'terrible people,' 'disgusting,' and 'scum,'" Vox's Amanda Taub writes.

This pattern has sometimes turned violent, as when a member of his security team choked and tackled a photographer at a rally:

Secret Service agent choke slams reporter pic.twitter.com/jdsHOlylSB — Joe Perticone (@JoePerticone) February 29, 2016

"The Thunderdome vibe at Trump events set my teeth on edge," Stevenson recalls. "Each time the mood tautened, I’d wonder: Is this the day a truly tragic thing happens?"

This kind of targeting of the press is classic Nixon. His initial 20-member "enemies' list" contained three journalists: columnist Mary McGrory, CBS's Dan Schorr, and LA Times national editor Edwin Guthman. Nixon and his chief of staff, H.R. Haldeman, were recorded discussing how to "go after" Schorr; Haldeman mentions that he'd already gotten the FBI to look into him and had the IRS investigating Schorr and McGrory. "FBI agents around the country did twenty-five interviews on Schorr in less than six hours," Nixon biographer Richard Reeves writes.

The threats were often physical. When called for comment on a Watergate story, Nixon's Attorney General turned reelection campaign manager John Mitchell told Carl Bernstein that "[Washington Post publisher] Katie Graham's gonna get her tit caught in a big fat wringer if that's published."

Nixon took things a bit further with columnist and muckraker Jack Anderson, upon whom he blamed his 1960 loss. (Anderson published a column about a "loan" Nixon's brother received from the billionaire Howard Hughes shortly before the election.) Nixon's team actually considered putting a hit out on Anderson, and did sic some CIA agents on him, Anderson's former intern Mark Feldstein recalls:

White House aide Jeb Magruder told colleague G. Gordon Liddy that Nixon "would sure like to get rid of [Anderson]." Along with fellow White House "plumber" E. Howard Hunt, Liddy met with a CIA operative to discuss options---drugging Anderson with LSD, poisoning his aspirin bottle, staging a fatal mugging. Nixon's men then turned to more subtle measures, unsuccessfully trying to discredit Anderson by planting false evidence that he was gay or trying to get him drunk before his radio show. But none of these tactics worked; the straight-arrow Anderson was a father of nine and a teetotaler, not easy to discredit. But the Nixon Administration still didn't give up. In "Operation Mudhen"---an apparent synonym for "muckraker"---a team of CIA agents began following Anderson when he met with sources. Undaunted, Anderson set his teenage children on the operatives, who fled before a laughing Anderson brood gleefully taking photos of the government spies.

The FBI then targeted Anderson by arresting his partner, Les Whitten, "and then used that arrest as a pretext for subpoenaing Anderson and Whitten's telephone records — allowing them to trace the reporters' sources," Feldstein writes.

It's impossible to say ahead of time whether Trump will use the powers of the presidency to target the press the way Nixon did. But he's certainly promising to use the government to crack down on journalists who criticize him.

"One of the things I'm going to do if I win … I'm going to open up our libel laws so when they write purposely negative and horrible and false articles, we can sue them and win lots of money," he said at a February 26 rally. "We're going to open up those libel laws. So when The New York Times writes a hit piece which is a total disgrace or when The Washington Post, which is there for other reasons, writes a hit piece, we can sue them and win money instead of having no chance of winning because they're totally protected."

Now, there might be a case to be made that US libel laws are too lenient on journalists. But coming from a presidential candidate promising to use the power of the state to crush his enemies in the press, the proposal doesn't exactly sound anodyne.

Nixon supported violence against protesters, just like Trump does

Trump's vehement hatred of the press is matched only by his loathing of protesters — and his tolerance and encouragement of violence against them:

When a Trump supporter punched a protester in the face and was charged with assault, Trump said he'd look into paying the assailant's legal fees.

In an Iowa speech, he declared, "If you see somebody getting ready to throw a tomato, knock the crap out of 'em, would you? Seriously. Okay? Just knock the hell — I promise you, I will pay for the legal fees. I promise. I promise."

At a November event in Alabama, a Trump supporter reportedly "punched and attempted to choke" a protester. Trump commented that "maybe he deserved to get roughed up."

At an event in Michigan, as a protester was being dragged out, Trump declared, "Get him out. Try not to hurt him. If you do I’ll defend you in court."

Similarly, "Nixon thrived on adversarial relations with demonstrators," Drew says. One case in particular — the so-called "hard hat riot" of 1970 — has eerie parallels to Trump's behavior:

On May 8, 1970, Peter Brennan, the leader of the New York City–area construction workers union, deployed about 200 construction workers to counterprotest an antiwar rally near Wall Street. The workers wound up savagely beating the protesters, and about 70 people wound up injured, including several police officers.

Rather than stopping after his members turned into violent thugs, Brennan and the construction workers began holding daily rallies. The actions caught the attention of White House aide Chuck Colson, who saw the protests as "an inviting opportunity to counterbalance the growing antiwar movement," as historian Edmund Wehrle writes, and encouraged the protests to continue. In a matter of weeks Nixon invited Brennan and the organizers of the hard-hat protests to the White House, where Brennan presented the president with a hard hat. After Nixon was reelected, he rewarded Brennan by naming him secretary of labor.

This wasn't an isolated incident. In 1971, Nixon and Haldeman discussed using Teamster "thugs" to attack demonstrators, to "knock their heads off," in Nixon's words. "Sure. Murderers," Haldeman replies. "Guys that really, you know, that's what they do."

Nixon directly egged on his own protesters too. In late 1970, he went campaigning nationwide for midterm candidates, in part hoping to provoke confrontation. He got it on October 29, after a speech in San Jose, when 2,000 protesters surrounded his motorcade. (Haldeman, his chief of staff, wrote in his diary, "We wanted some confrontation and there were no hecklers in the hall, so we stalled departure a little so they could zero in.")

Nixon got out of his car, stood on its hood, and flashed his trademark V-sign; "I could not resist showing them how little respect I had for their mindless ranting." He was promptly pelted with vegetables, eggs, and, Nixon claimed, rocks (this last detail is the most dubious). Drew notes that the incident backfired, making Nixon look awful and unpresidential (especially in contrast to Democratic Sen. Edmund Muskie, who delivered a well-received, calm televised address before the midterms)— but it was intended to make his enemies look deranged.

"Using demonstrators to your own advantage is what Nixon did, and what Trump is doing," Drew says. Indeed, you can see parallels in Trump's association of protesters with various political causes his supporters revile. He has attacked protesters as Bernie Sanders supporters attempting to sabotage him; in one case, he accused a protester of being tied to ISIS.

It's of course impossible to say if Trump will govern in as lawless a manner as Nixon as well. But Naftali isn't optimistic. "Using government as a tool of vengeance is horrible, and Nixon tried to do it and to some extent did succeed," he says. "Trump acts as if he has the same vision of the appropriate use of government power."