Jonathan Bernstein is a Bloomberg Opinion columnist covering politics and policy. He taught political science at the University of Texas at San Antonio and DePauw University and wrote A Plain Blog About Politics. Read more opinion LISTEN TO ARTICLE 3:26 SHARE THIS ARTICLE Share Tweet Post Email

Photographer: Alex Wong/Getty Images Photographer: Alex Wong/Getty Images

It didn’t take long during the second day of public impeachment hearings, in which the House Intelligence Committee is questioning former Ambassador to Ukraine Marie Yovanovitch, to get not one, not two, but three examples of how President Donald Trump undermines those who try to defend him.

First, Trump released a written summary on Friday of his first phone call, on April 21, with the new Ukrainian president, Volodymyr Zelenskiy. That’s something Trump has been talking up over the last several days as if it could somehow clear him of the improper things he said on the now-famous second call, on July 25: the one where he asked Zelenskiy to do him the “favor” of working with his private lawyer, Rudy Giuliani, on an investigation of his political rival Joe Biden. The committee’s ranking Republican, Devin Nunes of California, was so eager to cooperate that he read the whole thing out loud during his opening statement.

And yet as the national-security journalist Marcy Wheeler noted, the new call record “backfired in two ways.” For one thing, the original White House readout of the call claimed that Trump had pushed Zelenskiy to clean up corruption, but there was no mention of that in the call record released on Friday. For another? It turns out that Trump, in the April call, had already invited Zelenskiy to visit the White House. This contradicts a point Republicans tried to make on Wednesday, during the first day of public hearings, that Trump’s delay in scheduling the visit (and delivering military assistance after Congress had already appropriated the money for it) represented a prudent wait for an assessment of a new leader. As it turns out, Trump was perfectly prepared to host Zelenskiy until he realized he could use the invitation to leverage help for the 2020 campaign.

As Yovanovitch began to testify, and just about at the point where she said that she felt personally threatened by Trump’s comments about her in the July 25 call, Trump then tweeted a personal attack on her. As the committee chair, California Democrat Adam Schiff, pointed out, this confirmed that Trump was engaging in a pattern of witness intimidation, a crime. Perhaps just as bad for Republicans trying to defend Trump, however, this kind of petty and nasty attack put them in a position of defending the indefensible. As if to make that point, Republican Representative Elise Stefanik of New York told reporters during a break that she disagreed with Trump’s tweet. In other words, Trump managed to provide evidence for the point Democrats were making, and did so in a way that Republicans couldn’t stomach.

But Trump’s tweet did more than that. Schiff broke into the Democratic counsel’s questioning to read it to Yovanovitch and get her reaction, a moment that made for riveting television. That undermined the big talking point that the White House had pushed and Republicans had repeated on Wednesday, the claim that the hearings were boring.

Providing supporters with safe ground is important to Trump’s future. Most politicians are willing to go pretty far out on rhetorical limbs to advance what they see as their political interest. What they don’t like is to be exposed as fools soon after doing so. The real importance of the “smoking gun” tape that ended Richard Nixon’s presidency was that it discredited his supporters for repeating what turned out to be lies, and convinced them that Nixon would go on doing that to them as long as they were willing to stick with him. They might have been willing to let him shred the Constitution, but they weren't willing to look like idiots.

Trump is repeatedly giving Republicans that same choice. So far, they've been willing to go along. But each time he pushes them, it makes it a little more likely they’ll eventually make the same choice that Republicans made in August 1974.

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.