Bill Cohen served as an influential three-term U.S. senator, as well as secretary of defense, and is a respected global thinker. He believes his defining political moment occurred one summer four decades ago.

As a 33-year-old freshman Republican representative from Maine, he was a central figure in the House Judiciary Committee’s vote on July 27, 1974, to impeach President Richard Nixon.

It was one of the most important and high-minded deliberations in congressional history. Unfortunately, it failed to become a model for subsequent actions. The impeachment of President Bill Clinton and the calls to do so for George W. Bush and Barack Obama are petty and frivolous by comparison.

Cohen recalls members struggling with the impeachment standard of “high crimes and misdemeanors.” As with Elizabeth Drew’s compelling 1975 account, “Washington Journal: Reporting Watergate and Richard Nixon’s Downfall,” which recently was reissued, Cohen’s recollections are a reminder American politicians can rise and respond to crises.

Cohen, who ignored advice in 1972 not to go on the Judiciary Committee because “it doesn’t do anything,” notes lawmakers were devoid of precedents and could look only to English law and the politically tainted effort used to impeach President Andrew Johnson more than a century earlier.

There was, however, the voluminous record of the charges, including the nationally televised hearings of the special Senate Watergate committee. To prepare for the impeachment deliberations, Cohen memorized the testimony before the Senate panel to compare it with his committee’s hearings and a selection of taped conversations from the White House.

“We realized impeachment had to be of such gravity,” he says, it would need to rely on “the fundamental foundation of the Constitution if you’re going to remove a president that people have just elected.”

The outcome was in doubt well into July. It was incredibly tense. One member had a severe bleeding ulcer, another lost his voice. Rep. Hamilton Fish, R-New York, under the watchful presence of his Franklin D. Roosevelt-hating and Nixon-loving father of the same name, moved toward impeachment. As he raised questions, Cohen was called a “Judas and traitor” by Republicans in his home state, and his children were threatened.

The committee functioned under the unexpectedly skillful leadership of Chairman Peter Rodino, previously thought to be a New Jersey machine politician.

The swing bloc — a half-dozen Republicans, including Cohen, and three Southern Democrats zeroed in on charges of obstruction of justice. In particular, that Nixon directed a coverup of the attempted break-in by campaign operatives into the Democratic National Committee headquarters in the Watergate building and abuse of power, including using the Central Intelligence Agency for domestic political purposes, trying to get the Internal Revenue Service to go after political opponents and breaking into a psychiatrist’s office to find dirt on a leaker, Daniel Ellsberg.

A crucial figure in these fascinating and substantive deliberations was Rep. Charles Wiggins, R-California, the president’s chief defender. He was “a great lawyer,” who forced the impeachment advocates to develop a deeper and more substantive case, Cohen says.

On July 27, the committee voted 27-11 to impeach the president, with all the Democrats and six Republicans, including Cohen, in the majority. A week later, other court-ordered tapes were released that clearly implicated the president; Wiggins and most other Republicans came out against Nixon, who then resigned.

The panel focused only on the big fundamental issues. It rejected impeaching the president for evading taxes or ordering the illegal bombing Cambodia.

Successors ignored this precedent in voting to impeach Clinton for lying about sexual relations or proposing to remove George W. Bush for the Iraq War or his signing statements to interpret legislation, and now some Republicans are calling for proceedings against Obama for executive actions his opponents consider improper.

“You look at the substance of these charges and you say, this is not serious,” Cohen laments.

Forty years ago, after the committee voted early Saturday evening — and it was clear a president was going to be removed for the first time — I walked from the committee room in the Rayburn building to the Capitol. The flag was flying, tourists were milling about, there were no troops in the streets: It was a seminal American moment.

Albert R. Hunt is a Bloomberg View columnist. He was formerly the executive editor of Bloomberg News, directing coverage of the Washington bureau.