Pull up your bell bottoms, slip on your clogs and turn up the Roberta Flack: Today, we’re gonna testify like it’s the 1970s.

“Did you ever convey an order to break into the Democratic headquarters at the Watergate Hotel?” asked Rep. Louie Gohmert, R-Texas.

“What was the Saturday Night Massacre?” asked Rep. Sheila Jackson Lee, D-Texas.

“Early on in the Nixon coverup, you told Nixon there was a cancer on the presidency,” observed Rep. Hank Johnson, D-Ga.

And there at the witness table sat none other than John Dean, White House counsel to President Richard Nixon during Watergate, who did prison time and lost his law license for his role in the coverup.

Forty-six summers ago, Dean broke with Nixon in testimony before Sam Ervin’s Senate Watergate committee, propelling Nixon down the path toward impeachment. Now a cable-news pundit and scold of misbehavior by (Republican) presidents, Dean returned to Capitol Hill on Monday to draw parallels between Nixon and President Trump.

“The last time I appeared before your committee was July 11, 1974, during the impeachment inquiry of President Richard Nixon,” he told members of the House Judiciary Committee. Now 80, his thin white hair replacing the boyish mane and narrow readers replacing his owlish spectacles of yore, Dean slouched over the witness table, connecting dots from the Watergate Hotel to Trump Tower.

Dean drew parallels between the falsehoods told by Trump officials and those told by John Mitchell, H.R. Haldeman and John Ehrlichman; between the firing of James Comey and the firing of Archibald Cox; between efforts by both Trump and Nixon to shut down FBI probes; between the pardons dangled by both men; between attempts by Trump to get Donald McGahn to lie and Nixon’s attempts to get Dean to lie; and between the refusal by McGahn and the refusal by Elliot Richardson and William Ruckelshaus to fire prosecutors.

“The Mueller report, like the Watergate Road Map, conveys findings, with supporting evidence, of potential criminal activity,” Dean testified, later adding that “it’s quite striking and startling to me that history is repeating itself, and with a vengeance.”

Of course, Dean is of limited value in the year 2019. He has no particular expertise on Trump, and he’s already on record saying President Ronald Reagan’s Iran-Contra affair and President George W. Bush’s Iraq War were both worse than Watergate. (Dean’s 2004 book about Bush: “Worse than Watergate.”) He called Trump “Nixon on steroids and stilts” well before special counsel Robert Mueller reached his conclusions.

But even a casual association of Trump with Watergate serves Democrats’ purposes, because Watergate remains the gold standard of presidential scandals. “Was it worse than Watergate? Yes,” declared Rep. Adam Schiff, D-Calif., the chairman of the Intelligence Committee, continuing a tradition of politicians likening political scandals to Nixon’s downfall, including the Chappaquiddick incident, the Clintons’ Whitewater and “Filegate” scandals, George W. Bush’s warrantless wiretapping and Barack Obama’s Solyndra and Benghazi imbroglios (as well as the birth certificate charade).

Trump repeatedly declared Hillary Clinton’s email flap to be “many times worse than Watergate.” Now, he’s saying that investigators’ surveillance of his campaign is “worse than Watergate.”

The current situation is worse than Watergate – not necessarily in the illegality (history will judge that), but in the way the political system handles the investigation.

During Dean’s first go-round, serious legislators put country before party and launched honest and sober investigations of Nixon’s misbehavior. But now, Republican lawmakers reflexively defend Trump’s impropriety and support his refusal to allow aides to testify before congressional inquiries.

Meanwhile, many Democrats, rather than following the Watergate model of lengthy investigation before impeachment, are clamoring for immediate impeachment proceedings.

At Monday’s hearing, the chairman, Jerrold Nadler, D-N.Y., pleaded with colleagues to treat the session with the “seriousness it deserves.”

As if.

Georgia Rep. Doug Collins, the committee’s ranking Republican, needled: “This committee is now hearing from the ’70s, and they want their star witness back.”

Rep. Matt Gaetz, R-Fla., accused Dean of building a “cottage industry out of accusing presidents of acting like Richard Nixon.”

Gaetz continued: “Do you believe if we turned the lights off here and maybe lit some candles, got out a Ouija board, we could potentially raise the specter of Richard Nixon?”

“I doubt that,” Dean replied dryly.

At this, Gaetz lost control of his metaphors: You’re hearing “the ghost of Christmas past. … We’re here reopening the impeachment inquiry potentially into Richard Nixon. … (We’re) sort of playing out our own version of ‘That ’70s Show.’ ”

Maybe so. But does the sequel have the same ending?

Dana Milbank is a columnist for The Washington Post. He can be contacted at:

dana.milbank@washpost.com