Republican Sen. Mike Lee of Utah responded to Donald Trump’s felony conviction with a predictable tantrum, circulating a conspiratorial letter blaming the White House for a case it had nothing to do with, and vowing to punish the Senate with procedural roadblocks. Lee then looked for GOP senators who’d stand with him.

It didn’t take long for some of the institution’s most far-right members to attach their names to the Utahan’s letter, even as Senate Republican leaders kept their distance. It was exactly the sort of radical gambit that serious senators roll their eyes at.

Which made it all the more notable when Sen. Marco Rubio joined some of his unserious colleagues and signed Lee’s absurd letter over the weekend.

For the Florida Republican, this was the latest in a series of similar steps. In recent weeks, Rubio has refused to say whether he’d accept the results of the 2024 presidential election. Rubio has tried to pretend that Democrats are election deniers. Rubio has used increasingly hysterical partisan rhetoric, describing President Joe Biden as “demented,” and condemning White House officials as “wicked.” Rubio has even compared the U.S. justice system to Cuba’s and was caught lying about the jury instructions in Donald Trump’s hush-money case.

A Washington Post fact-check piece this week noted that the senator has even begun peddling debunked claims about the 2020 presidential election.

And therein lies the point. Senators who want to be respected and taken seriously don’t behave like this. Senators looking to score points with Mar-a-Lago behave precisely this way.

There’s no great mystery here. Rubio wants to be a leading contender for Donald Trump’s 2024 ticket, which necessarily means the longtime lawmaker has to join the GOP’s race to the bottom, and engage in antics that he almost certainly recognizes as ridiculous.

What makes this case all the more jarring, however, is the familiarity of the circumstances.

As part of his 2016 presidential campaign, Rubio initially presented himself to his party’s primary voters as a young, serious visionary. What he soon discovered, however, was that there was no real appetite for such a candidate — leading the senator to quickly switch gears: The Floridian, pandering to a base that appeared fond of buffoons, started telling audiences that Trump, among other things, might urinate on himself. Rubio also mocked Trump’s hair and face, and even made vulgar jokes about Trump’s genitals.

That didn’t work, either — GOP primary voters had already settled on one crude loudmouth and saw no need for an imitator — and Rubio exited the race following an embarrassing showing in his own home state. But at the time, the senator also seemed to realize that he’d gone too far, and it was time to reclaim some of the self-respect he’d sacrificed on the campaign trail.

In fact, in May 2016, amidst chatter that he was in the running for Trump’s ticket, Rubio categorically ruled out the idea. “While Republican voters have chosen Donald Trump as the presumptive GOP nominee, my previously stated reservations about his campaign and concerns with many of his policies remain unchanged,” the senator said at the time. “He will be best served by a running mate and by surrogates who fully embrace his campaign.”

Months later, Rubio was among the Republican officials who were quick to condemn the comments Trump made on the infamous “Access Hollywood” recording.

After the 2016 election, Rubio ultimately became chairman of the Senate Intelligence Committee, and oversaw the panel when it investigated the connections between the Trump campaign and its Russian benefactors. The Rubio-led investigation ultimately uncovered, among other things, a “direct tie between senior Trump Campaign officials and the Russian intelligence services.”

After the 2020 election, when Trump was pressing GOP lawmakers to reject certification of Biden’s presidential election victory, Rubio was among the Republicans who ignored Trump’s pleas.

It appeared that the Floridian cared anew about his reputation. Those cares have apparently been discarded once again.

Or put another way, in 2016, Rubio sacrificed his self-respect in the hopes of advancing his ambitions. In 2024, it’s pitiful to see him do it again.

This article was originally published on MSNBC.com