Let’s dust off the history books and turn back the clock 45 years, to an event that resonates today.

On Feb. 21, 1974, the House Judiciary Committee, having already spent four months probing Richard Nixon’s serial perfidies, released a pivotal report about impeachment. Committee counsel John Doar — a registered Republican — wrote that this “constitutional remedy,” which had its roots in British practice, should be pursued only when a president commits “serious offenses against the system of government … undermining the integrity of office, disregard of constitutional duties and oath of office, arrogation of power, abuse of the government process, adverse impact on the system of government.”

Read those criteria. Then ask yourself whether the 2019 House Judiciary Committee isn’t obligated, by dint of its constitutional duty, to dig deep into the burgeoning evidence of Donald Trump’s serial perfidies.

Some Democrats fear that the committee — helmed by Jerry Nadler, thanks to the midterm surge that threw the House Republicans out of power — is playing with fire, that its newly-announced probe into “allegations of obstruction of justice, public corruption and other abuses of power” will backfire against Democrats and give Trump sufficient rhetorical ammo to survive in 2020.

But I don’t buy it. Trump is politically weak with few prospects of getting stronger, and there’s every reason to believe, in the months ahead, that the sheer weight of the evidence will convince the electorate (outside Trump’s cult) that even an official impeachment push is warranted.

Nadler said earlier this week, “We do not now have the evidence all sorted out to do an impeachment. Before you impeach somebody, you have to persuade the American people that it ought to happen.”

And it just so happens that the ground is well-seeded for a persuasion effort.

According to the newly-released Quinnipiac poll, 64 percent of Americans (including 33 percent of Republicans) believe that Trump committed crimes before he was president, and a 45 percent plurality of Americans believe that he has committed crimes during his presidency. Also, 58 percent say that Congress should do more to investigate Michael Cohen’s documented claims that Trump has engaged in “unethical and illegal behavior,” and 65 percent (including 26 percent of Republicans) say that Trump is “not honest.”

Granted, only 35 percent of Americans say that Congress, at this time, should be initiating impeachment proceedings (Nadler’s committee is a long way from doing that), but it’s important to remember that only 43 percent of Americans supported Richard Nixon’s impeachment and removal at the time of Doar’s memo — only six months before Nixon escaped impeachment by quitting his job.

But all these political calculations elide the big picture.

In times of crisis — and this crisis is unprecedented — our elected leaders cannot shirk their duties. They cannot numb themselves to the serial abuses to our constitutional system and national security. Impeachment is inevitable if the sheer weight of the evidence warrants it, and the politics of impeachment will take care of themselves. It’s true that Trump has something Nixon never had — a propaganda cable network, which dutifully killed its pre-election story about the Stormy Daniels hush payments — but, lest we forget, Fox News speaks mostly to the cult, not to the American majority.

Last summer, in Helsinki, when Trump sided with Putin against our intelligence community, former CIA director John Brennan said that Trump’s “treasonous” behavior “rises to and exceeds the threshold of high crimes and misdemeanors.” Trump’s Helsinki betrayal, by itself, meets the impeachment standards detailed by John Doar in 1974. Indeed, we’ve reached the point where selling out our intelligence community, in obeisance to a hostile power, is merely the tip of the tip of the iceberg.

Which is why House Judiciary chairman Nadler was correct to point out, in his Monday letters demanding documents from 81 individuals and entities, that “Congress has a constitutional duty to serve as a check and balance.” His probe will proceed slowly (far too slowly for today’s hyper 24/7 news cycle), but that’s the way credibility is built.

Back in the Watergate era, the Judiciary panel was frequently attacked, by both the left and right, for moving too slowly, but by the time it determined that the weight of the evidence warranted Nixon’s impeachment — nine months after its probe began — its momentum was unstoppable.

On July 24, 1974, chairman Peter Rodino opened the impeachment hearings with these words: “Our judgment is not concerned with an individual, but with a system of constitutional government … For almost 200 years every generation of Americans has taken care to preserve our system and the integrity of our institutions against the particular pressures and emergencies to which every time is subject … Let us leave the Constitution as unimpaired for our children as our predecessors left it to us.”

Forty-five years later, may those last words resonate with us.

Dick Polman is the national political columnist at WHYY in Philadelphia and a “Writer in Residence” at the University of Pennsylvania. Email him at dickpolman7@gmail.com.