Sen. Mitt Romney (R-Utah) has been in politics long enough to understand that his appearance at a Black Lives Matter protest in Washington on Sunday served as a rebuke of President Trump. Romney has mastered the art of getting under Trump’s skin by passively highlighting Trump’s weaknesses, and the protest certainly achieved that goal.

On Monday morning, Trump tweeted a video snippet of Romney at the march, disparaging the senator and 2012 Republican nominee with a sardonic “what a guy.”

“Hard to believe, with this kind of political talent, his numbers would ‘tank’ so badly in Utah!” Trump wrote — apparently not knowing that Romney is, in fact, quite popular in his state.

Asked about Romney’s appearance in the march at a news briefing Monday, White House press secretary Kayleigh McEnany offered much nastier criticisms.

“Mitt Romney can say three words outside on Pennsylvania Avenue,” she replied, “but I would note this: that President Trump won 8 percent of the black vote. Mitt Romney won 2 percent of the black vote.”

First of all, this is wrong. Exit polling shows that Romney earned 6 percent of the black vote in 2012, essentially equivalent to the 8 percent Trump earned.

Second, Romney was running against Barack Obama, the first black president in U.S. history. Both Romney and former senator John McCain of Arizona, Obama’s 2008 opponent, did worse with black voters than prior Republican candidates.

Third, Trump’s performance with black voters was actually the worst of any Republican facing a white Democratic opponent in the era of modern exit polling (though he ran essentially equal to George W. Bush in 2000 and Ronald Reagan in 1984).

Fourth, a Post-ABC News poll conducted in October 2012 found that Romney’s favorability with black voters was over 20 percent. In October 2016, Trump’s favorability was under 10 percent.

Beyond those things, though, great point.

What’s remarkable isn’t only that this argument was bad both on the merits and the details. It’s that McEnany offered it at all. That, instead of simply waving off the question and declining to engage in nitpicking with Romney, particularly on such an emotional issue, the White House decided to jump in with both feet. Not only could Trump and his team not abide Romney’s quiet message of opposition, it also had to continue to try to deride him personally and mock his most public failure.

Part of the reason for this is obviously that Trump’s reelection campaign has invested so heavily in making a pitch to black voters. After having benefited in 2016 from a drop in black turnout, Trump’s team clearly hopes to either woo some percentage of black voters in November or to convince them that Trump is good enough and therefore not to back Biden. Having a Republican in the streets of Washington advocating a position of sympathy with black Americans that highlights Trump’s lack of a similar position is simply unacceptable.

To whom was McEnany trying to send a message, anyway? Clearly to Romney, though Trump’s repeated efforts to bash the senator haven’t dissuaded him from his protests against the president. If anything, they may have had the opposite effect. In part, McEnany smacked Romney because Trump wanted her to smack Romney, and because Trump’s base relishes these sorts of disparagements.

It seems unlikely, though, that there are black voters who are going to see Romney’s appearance at the march and reconsider it in light of how he did with black voters in 2012.

So McEnany switched to a different tack, criticizing Romney’s relationship with black Americans more broadly, as though Trump and the senator were in a tough primary fight.

“Mitt Romney has a lot of words,” she said when continuing her response. “Notably, he said that 47 percent of the nation is dependent upon government, believes they are victims, believes that the government has a responsibility to care for them. Those were Mitt Romney’s words not too long ago. The president takes great offense to those words. That’s not America.”

Those words came from a leaked recording during the 2012 campaign. They were widely reported at the time and broadly criticized.

One person who didn’t criticize the comments was Donald Trump. During an appearance on NBC News’s “Today” show at the time, Trump said “we’ve seen enough apologizing already” and that Republicans “have to fight fire with fire, the Republicans have to get tougher or they’re going to lose this campaign.” This was very much in keeping both with Trump’s role in 2012 — self-appointed attack dog for Romney — and Trump’s approach to politics.

Notice, by the way, that Romney didn’t mention black people. It’s McEnany who appears to be suggesting that Romney was referring to black people, a criticism which was raised at the time. McEnany assumes either that people will remember that particular criticism or that they should understand Romney’s comments to be referring to black Americans.

Again, the White House response should be seen as being less about Romney than about the way in which Romney drew attention to Trump’s troubles with black voters. McEnany’s response then transitioned to the standard patter the administration and Trump’s campaign deploy as they seek to appeal to black Americans: She mentioned the creation of “opportunity zones” and funding for historically black colleges. Trump likes to say he’s done more for black Americans than any other president, which has not been found to be true by The Post’s fact-checkers.

“Those kind of actions on the part of the president stand in stark contrast with the very empty words of Senator Romney,” McEnany said in conclusion.

The words Romney used were these: He was marching to “find a way to end violence and brutality and to make sure that people understand that black lives matter.” McEnany did use the phrase “black lives matter” during Monday’s briefing, stating twice that “all black lives matter” as she noted the death of black retired police officer David Dorn during a looting incident.

On Saturday, Romney shared a photo of his father, George, once the governor of Michigan and later an official in President Richard M. Nixon’s administration.

Romney’s presentation of his father’s legacy on race was reinforced by others. Trump’s father’s history on issues of race, for what it’s worth, is less robustly positive.