Senate Majority Leader Mitch McConnell (R-Ky.) speaks Tuesday about President Trump’s attacks on four minority congresswomen. (Jim Lo Scalzo/EPA-EFE/Shutterstock)

It’s been four years since Donald Trump launched his first attack on a member of Congress.

And the arc of Republican lawmakers can be measured between how they denounced his initial broadside to their slightly supportive response over the past four days to his attacks on four freshman House Democrats.

Just a month into the 2016 presidential campaign, Trump used a summit of Christian leaders on July 18, 2015, to belittle Sen. John S. McCain (Ariz.), the 2008 GOP presidential nominee. “He’s not a war hero,” Trump said, discounting the 5½ years McCain spent as a prisoner of war in Vietnam after his Navy jet was shot down.

“I like people that weren’t captured.”

This week, in comments that began Sunday on Twitter and continued, including again Wednesday on the White House lawn, Trump said the four nonwhite Democratic congresswomen “hate our country” and should “go back” to the countries where their families were from.

By Tuesday morning, as House GOP leaders began their weekly briefing, Rep. Liz Cheney (Wyo.) set the tone for how Republicans would handle the latest Trump controversy: Embrace the line of attack against those Democrats, but avoid such an obvious racist trope.

House Minority Leader Kevin McCarthy (R-Calif.), left, Republican Conference Chair Liz Cheney (Wyo.) and Minority Whip Steve Scalise (R-La.) take turns speaking to reporters Tuesday. (J. Scott Applewhite/AP)

In a 470-word opening statement, Cheney accused the quartet of trying to “impose the fraud of socialism” and enabling “anti-Semitism,” adding that they “blame America first” and support proposals that would create “massive new government dependency.” She said their policies would eliminate “all private health insurance” and “destroy Medicare.”

But, the No. 3 House GOP leader said, Republicans do not have anything against the ethnic identities of Reps. Alexandria Ocasio-Cortez (N.Y.), Ilhan Omar (Minn.), Ayanna Pressley (Mass.) and Rashida Tlaib (Mich.), whose testimony Friday about disturbing conditions inside detention centers along the U.S.-Mexico border prompted Trump’s outburst.

“So, no, our opposition to our colleagues’ beliefs has absolutely nothing to do with race or gender or religion. We oppose them and their policies because their policies are dangerous,” Cheney said.

By Tuesday afternoon, Senate Majority Leader Mitch McConnell (R-Ky.) picked up where Cheney left off and lambasted Ocasio-Cortez for referring to migrant detention centers as “concentration camps” and blasted the “far left” for lobbing racism allegations at many people, including House Speaker Nancy Pelosi (D-Calif.).

Then-presidential candidate Donald Trump spoke at a July 2015 rally in Oskaloosa, Iowa, after he had sparked controversy earlier that month by saying that Sen. John McCain, a former prisoner of war, was not a war hero. (Scott Olson/Getty Images)

He bemoaned that the “most vile accusations and insults against our nation” have become routine, before finally hinting that the president may have said something wrong.

“All of us, from the president, to the speaker, to freshman members of the House, all of us have a responsibility to elevate the public discourse. Our words do matter,” McConnell said.

The official response from top congressional Republicans is to express glancing disapproval of racist tones from Trump and instead elevate the four first-term lawmakers to a level where they hold as much control over the national discourse as the president of the United States.

Asked whether Trump held any special obligation to tone down the rhetoric, McConnell pivoted to the all-sides argument: “I think I’ve just said I think everybody ought to tone down their rhetoric. We have examples of that across the ideological spectrum in the country.”

Trump’s attacks on McCain followed a path similar to those this week, after the senator had become an early, vocal critic of the candidate’s rhetoric about Mexicans being “rapists” sneaking across the border. That’s what prompted his initial attack on McCain’s POW status, which brought immediate, forceful denunciation from Republicans in Washington.

“America’s POWs deserve much better than to have their service questioned by the offensive rantings of Donald Trump,” tweeted Sen. Marco Rubio (Fla.), then a presidential contender.

Sen. Lindsey O. Graham (S.C.), a close friend of McCain, accused Trump of lacking “respect for those who have served.”

Sean Spicer, who went on to serve as Trump’s White House press secretary, issued a statement as a top official at the Republican National Committee, calling McCain a war hero and praising his sacrifice.

“There is no place in our party or our country for comments that disparage those who have served honorably,” Spicer said.

But the blowback had no impact. Just as he doubled down Monday on his racist comments about Democrats, Trump immediately kept up the attack on McCain on Sunday talk shows the day after his initial comments. He refused to apologize and claimed to be speaking on behalf of veterans who were not captured.

“People that fought hard and weren’t captured and went through a lot, they get no credit. Nobody even talks about them,” he said on ABC’s “This Week.”

Slowly over time, Trump wore down most of these Republican critics. They fell in line — Graham’s only criticism of Trump, during an appearance Monday on Fox News Channel, was that he distracted from policy disputes with the likes of Ocasio-Cortez. Some, such as former senators Bob Corker (Tenn.) and Jeff Flake (Ariz.), eventually retired in the face of Trump-infused backlash.

Or, in the case of McCain, they died.

Sen. Mitt Romney (R-Utah), who was one of the first to defend McCain four years ago, remained an outlier this week, holding the president to a higher standard than the four lawmakers whose combined experience in Washington barely tops two years.

“The president’s clearly in a very different category than the other people in the political life, and that is that the president has a very unique and noble calling to bring together the entire country, to welcome and appreciate people regardless of their race or national origin, their creed, their ethnicity,” the 2012 GOP presidential nominee told reporters Monday evening.

“I think he failed very badly yesterday and today, and I think it’s unfortunate for the country. I think the comments were destructive and demeaning and in some ways dangerous,” Romney said.

He added that Trump’s words were “not what I believe my party stands for, it’s not what I believe the country stands for,” but he also suggested that there was little else he could do.

“Making a statement is, I think, the most powerful thing that one can do,” Romney said.

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