The John Bolton book bombshell represents the intersection of mendacity and greed.

The mendacity has been the dissembling and the lying by Donald Trump and his Republican enablers that the withholding of assistance to Ukraine was anything other than an old-fashioned mob shakedown: “You have a nice $400 million military aid package here. It would be a shame if anything should happen to it.”

The greed, of course, stems from Bolton's eager participation in that bipartisan 21st-century ritual of public servants racing to cash in the moment they leave the White House with a seven-digit book deal. Long gone are the days when Franklin Roosevelt longed for top aides with “a passion for anonymity.”

Bolton's book title, “The Room Where It Happened,” was presumably lifted from “Hamilton” by a clever book editor. Dating to Plutarch and continuing through the Ron Chernow biography on which the Broadway musical is based, studying the lives of public figures has been a way to learn moral conduct.

Republican senators like the politically imperiled Susan Collins and the retiring Lamar Alexander soon will cast one of the most historic votes of their long careers on Capitol Hill. The decision whether to hear impeachment testimony from Bolton and perhaps other witnesses will pit kiss-the-ring fealty to Trump against the demands of a fair trial.

As they wrestle with their decisions leading up to the eventual vote on whether to remove Trump from office, wavering senators might draw moral guidance from the lives of two Watergate figures who died recently. When their obituaries appeared, they were primarily familiar to those of us who once wallowed in Watergate.

A Nixon 'Plumber'

As a young White House lawyer, Egil Krogh arranged the odd-couple Oval Office meeting between Richard Nixon and Elvis Presley as part of the president's ineffectual war on drugs.

But everything changed for Krogh in 1971 after Daniel Ellsberg leaked to the press the internal history of the Vietnam War known as the Pentagon Papers. Krogh became one of the leaders of the internal White House group known as the “Plumbers” designed to discredit Ellsberg and thwart future leaks.

Krogh was in the room where it happened when former CIA operative E. Howard Hunt suggested that the Plumbers authorize an operation to break into the offices of Ellsberg's psychiatrist and steal his files. Krogh uncritically accepted Hunt's proposal — and that moral lapse changed his life.

As Krogh later wrote, “The premise of our action was the strongly held view within certain precincts of the White House that the president and those functioning on his behalf could carry out illegal acts with impunity if they were convinced that the nation's security demanded it.”

Those words have an eerie resonance as the Trump lawyers mount their defense.

In 1973, Krogh became the first Nixon aide to go to prison — based on his role in the Ellsberg burglary, which proved to be a prelude to Hunt helping orchestrate the 1972 Watergate break-in.

A Nixon Republican

Illinois Republican Tom Railsback was one of six GOP members of the House Judiciary Committee to vote for Nixon's impeachment in 1974.

Railsback was not a liberal Republican. He was more than anything a Nixon Republican. As Railsback put it in an emotional speech as the Judiciary Committee readied the articles of impeachment, “In my opinion Richard Nixon has done many wonderful things for his country. I wish the president could do something to absolve himself.”

A few weeks after Nixon resigned from office, Railsback was asked to give a luncheon talk to the Peoria Chamber of Commerce in his congressional district. Railsback reminisced to NPR's Scott Simon that he worried that the Nixon loyalists in the audience (many of them his friends and supporters) would attack him for his impeachment vote.

When Railsback arrived at the luncheon, a brief hush fell over the room. A lone man began applauding, then a few more joined in and finally an ovation morphed into a standing ovation. Railsback recalled being repeatedly told, “Tom, I disagree with that vote. But you did what you thought was right, and I'm glad you represent me.”

The 1970s may have been a different era when partisanship was not as vicious and Americans retained a grudging respect for legislators who voted their conscience.

But I wonder whether patriotic values have really changed that much or whether cowardice has just become accepted as the road of political convenience.

Everyone in the Senate should ask themselves this week: What will life be like when Donald Trump is no longer in the White House?

Barring a dramatic turnabout that seems unlikely no matter what Bolton says in his book or if he testifies in the trial, that moment will come, via election.

And Republicans who currently cower in fear of Trump tweets, brood about their political futures and worry about being booed at a Chamber of Commerce luncheon should think for a moment about the life lessons from the late Egil Krogh and Tom Railsback.

Walter Shapiro has covered the last 10 presidential campaigns.