People who get into fights with Donald Trump often end up diminished by it.

Just ask Marco Rubio, who in February 2016 broke some sort of ground when he introduced the "small hands" attack into presidential politics. "And you know what they say about guys with small hands," Rubio told crowds during the days he decided to transform himself from GOP contender into anti-Trump insult comic. A few weeks later, Rubio expressed regret about the "small hands" routine. "My kids were embarrassed by it, and if I had it to do again, I wouldn't," Rubio said.

Just ask Jeb Bush, who allowed himself to be drawn into brawls with Trump — brawls which there was no chance Bush, no match for Trump's insults, would win.

Just ask Ted Cruz, who made an informal peace with Trump for much of the campaign, then fought Trump in the final primaries, and finally released a campaign's worth of anger and bile at Trump just hours before the Indiana primary vote that knocked Cruz out of the race. Now, as a senator, Cruz has to work with, and support the policies of, the man who so got under his skin.

Of course, Rubio, Bush, and Cruz — and Carson, Christie, Fiorina, Paul, Kasich, Jindal, and others — had an excuse; they were running against Trump for the Republican presidential nomination. But others have tangled with Trump and found themselves diminished, too.

Just ask some of the more strident NeverTrumpers who have allowed Trump to live rent-free in their heads. Today, some are serious people doing non-serious things — I bought a pair of socks at Nordstrom! — because of a reflexive opposition to Trump.

Just ask CNN, which, in addition to its news reporting, has taken on what appears to be a network-wide air of snarkiness in its Trump coverage. That oppositional tone has raised the stakes for CNN when its journalists make mistakes, as they have recently. Yes, CNN's ratings have gone up, but its reputation has taken a hit. "Trump is indeed destroying CNN…by tempting them to destroy themselves," tweeted writer and former Breitbart editor Ben Shapiro recently.

And now ask Joe Scarborough and Mika Brzezinski, the TV hosts who once sang Trump's praises and were openly friendly with the presidential candidate but now bash and insult him daily. ("They've said he has dementia," RNC chair Ronna Romney McDaniel noted recently. "They've said he's stupid. They've called him a goon. They've called him a thug. They've said he's mentally ill.")

Scarborough and Brzezinski are engaged in a back-and-forth with Trump over…what? A facelift? Hand size? Who said what to whom? The argument, which appears to have started Thursday with Brzezinski's needling of Trump's hand size ("They're teensy!") took a turn when Scarborough and Brzezinski wrote in a Washington Post op-ed ("Donald Trump is not well") that, "This year, top White House staff members warned that the National Enquirer was planning to publish a negative article about us unless we begged the president to have the story spiked. We ignored their desperate pleas." TrumpWorld sources are telling some (decidedly not-in-the-tank) reporters a very different version of events, which suggests Scarborough and Brzezinski will be pulled into a he-said-they-said fight that is far different from the one they wanted.

Does anyone think that, by any measure other than notoriety, this episode will not diminish Scarborough and Brzezinski?

By the way, the diminishing effect does not apply to conventional political opposition. Senate Minority Leader Charles Schumer, for example, is opposing Trump at every turn but has refrained from going the most personal route. (Even if some of his accusations are flatly untrue.) Schumer is not smaller for it.

Of course one could say that Trump is at fault, that he regularly engages in spats that are beneath the dignity of the presidency. He should not, for example, respond in kind to "small hands" jabs. But Trump is Trump. He does what he does, which is what he did during the campaign and before. And now, in the White House, he has enlisted his media adversaries, wittingly or not, in a campaign against "fake news" that resonates with his core supporters.

"They like him, they believe in him, they have not to any large degree been shaken from him, and the more the media attacks him, the more it becomes a self-fulfilling prophecy on the side of the Trump supporters who fervently believe the media treat him unfairly," Tony Fabrizio, Trump's campaign pollster, told the Washington Post.

And for those who continue to jump into sloppy fights with the president? They will walk away diminished for having done so.