There are many muscular arguments against term limits, from arbitrarily depriving voters of their choice to the sterling Senate careers of long-serving legislators like Joe Biden and John McCain.

The case for term limits can be expressed in five words: Bob Corker and Jeff Flake.

In a remarkable Tuesday doubleheader — a blistering morning CNN interview by Corker and an emotional afternoon Senate speech by Flake — the two otherwise orthodox Republicans denounced their party’s Faustian bargain in embracing the presidency of Donald Trump.

Corker, the chairman of the Foreign Relations Committee, had already announced his retirement, while the Flake speech was built around the Arizona senator’s surprise revelation that he would bow out in the face of an uphill race for a second term next year.

Free from the party-line burden of 2018 re-election campaigns, Corker and Flake became the Capitol Hill embodiment of a Kris Kristofferson lyric: “Freedom’s just another word for nothin’ left to lose.”

Prior to Corker, other Foreign Relations chairmen have feuded with presidents of their own parties. During the height of the Vietnam War, Lyndon Johnson belittled his dovish foe, Sen. William Fulbright, as “unable to park his bicycle straight.”

Watch: More and More Republicans Speaking Out Against Trump’s Politics

‘The name-calling …’

But little in history tops Corker’s words in a CNN interview Tuesday morning about our first reality-show president: “I think at the end of the day, when his term is over, I think the debasing of our nation, the constant non-truth-telling and just the name-calling … will be what he’ll be remembered most for.”

In a just world, a tape of that interview will someday be running on a continuous loop at the Donald J. Trump Presidential Library. For “debasing” is the perfect word for the way that Trump has trampled on the norms of a democratic society as he panders to the worst instincts of his base.

That was also Flake’s theme as he rose to deliver his floor speech shortly after Trump had lunched with Senate Republicans. Flake’s words too were for the ages:

“We must never regard as normal the regular and casual undermining of our democratic norms and ideals. We must never meekly accept the daily sundering of our country — the personal attacks, the threats against principles, freedoms, and institutions [and] the flagrant disregard for truth or decency.”

Corker has a spotty history as a Trump nemesis. As Trump wrapped up the 2016 Republican nomination, Corker praised the bilious billionaire for “challenging the foreign policy establishment.” And after the election, he allowed himself to be considered for secretary of State.

Flake, with one of the most right-wing voting records in the Senate, is also an unlikely leader of the anti-Trump resistance. While he pointedly refused to endorse Trump during the 2016 campaign, Flake is disciple of Barry Goldwater and entitled his recent book, in Goldwater fashion, “Conscience of a Conservative.”

What many liberals forget is that most of the heroes of the drive to remove Richard Nixon from office had similarly flawed records.

Sam Ervin, the legendary chairman of the Senate Watergate committee, had been a leader of Southern filibusters against civil rights legislation. And during the final days, Goldwater himself was one of the Republican elder statesmen who told Nixon in August 1974 he had to resign for the good of country.

As long as the Republicans control both chambers of Congress, Democrats will remain bystanders in any attempt to contain the nation’s chaos theory president who governs through temper tantrums. If Congress reasserts its constitutional prerogatives in an ongoing struggle with Trump, it will be because Republicans like Corker, Flake and McCain will have led the way.

In a sense, Flake’s speech was reminiscent of another address by a first-term Republican senator — Margaret Chase Smith, who took on smear artist Joseph McCarthy in 1950. While senior legislators nervously worried about retaliation from the guttersnipe Wisconsin Republican, Smith bravely denounced McCarthy for turning the chamber into “a forum of hate and character assassination.”

There is a temptation to view the current apostasy in narrow legislative terms. The latest Trump fusillade at Corker was triggered, in part, by the Tennessee senator’s insistence that he will not vote for any tax cut legislation that increases the deficit.

With the Republicans practicing imaginative bookkeeping by claiming that a projected $1.5 trillion tax loss would be miraculously paid for by economic growth, Corker’s balanced-budget purity will likely cost the GOP a vote they can little afford to lose. Flake, on the other hand, has always been a loyal Republican on economic issues like tax cuts.

But that kind of small-bore vote-counting misses the larger point: Two respected Republican senators loudly broke with Trump on the same day.

McConnell weighs in

Tellingly, when Flake finished, Mitch McConnell rose not to defend Trump, but instead to say, “We’ve just witnessed a speech from a very fine man, a man who clearly brings high principles to the office every day.”

McConnell, of course, has been Trump’s enabler from the beginning, believing that tax cuts and partisan advantage trump any shred of principle. It would be a miracle of biblical proportions if McConnell somehow was inspired by his GOP colleagues. But the Watergate years were also a time of stunning turnabouts.

The first test of the new realities in the Senate will come next Monday when Corker presides over a Foreign Relations hearing featuring Rex Tillerson and James Mattis. And McCain, of course, chairs Armed Services. Maybe Trump is about to learn the power of Senate committee chairmen with a mission to tamp down an out-of-control president.

Roll Call columnist Walter Shapiro is a veteran of Politics Daily, USA Today, Time, Newsweek and The Washington Post. Follow him on Twitter @MrWalterShapiro.