THE MORNING PLUM:

Around the country, Republicans embroiled in tough primaries are increasingly emulating President Trump — by echoing his xenophobia, his veiled racist appeals, his attacks on the news media, and even occasionally his calls for imprisoning his political opponents.

Meanwhile, all indications are that Trump is heading for a serious confrontation with special counsel Robert S. Mueller III or Deputy Attorney General Rod J. Rosenstein over the Russia investigation.

So how long until multiple GOP primary candidates begin seriously running on the message that the Mueller probe is part of an illegitimate Deep State coup that justifies Trump shutting it down by any means necessary — that is, on a message of unabashed authoritarianism?

Two new articles — one in the New York Times, the other in National Journal — illustrate what’s happening in many of these GOP primaries. The Times piece, by Jeremy Peters, reports that in West Virginia, GOP Senate primary candidate Don Blankenship is running an ad that says: “We don’t need to investigate our president. We need to arrest Hillary … Lock her up!”

In multiple GOP races across the country, the Times piece reports, candidates are employing phrases such as “drain the swamp,” “build the wall,” “rigged system” and even “fake news.” The GOP Senate candidate in Tennessee ran an ad that promises to stand with Trump “every step of the way to build that wall,” and even echoes Trump’s attacks on African American football players protesting systemic racism and police brutality:  “I stand when the president walks in the room. And yes, I stand when I hear ‘The Star-Spangled Banner.'”

Meanwhile, National Journal’s Josh Kraushaar reports that in the Indiana Senate GOP primary, Mike Braun, the candidate who is most vocally emphasizing Trump’s messages — on trade, the Washington “swamp” and “amnesty” — appears to be gaining the advantage. Braun’s ads basically recast true conservatism as Trumpism in its incarnation as populist anti-establishment ethno-nationalism.

It gets worse. As the Indianapolis Star recently reported, one of the Indiana GOP Senate candidates has bashed “Crooked Hillary Clinton,” and all three have cast aspersions on the Mueller probe. One called it a “fishing expedition,” and another claimed: “Nothing’s been turned up except that Hillary Clinton is the real guilty party here.”

The question all this raises is whether there is a large swath of GOP primary voters who are fully prepared to march behind Trump into full-blown authoritarianism. The original plan was for Republicans to make tax cuts the centerpiece of their midterm campaign agenda. But in the Virginia gubernatorial race, the Republican candidate resorted to Trumpian xenophobia and a defense of Confederate statues to activate the GOP base, and in the Pennsylvania House special election, Republicans cycled the tax cuts out of their messaging. There just doesn’t appear to be much of a constituency for Paul Ryan Republicanism among today’s GOP voters.

The retirement of the House speaker himself has brought this recognition to a head. Figures such as Ryan and Sen. Marco Rubio were supposed to create a youthful, forward-looking aura around limited government, constitutional conservatism and tax-cutting, safety-net-shredding plutocracy, broadening their appeal to (and edging the GOP into a new accommodation with) 21st-century diversifying America. But Trump won, Ryan is retiring to spend more time with his faded college Ayn Rand poster, and on his way out Ryan has acquiesced to Trump’s nativist nationalism and has lent his tacit support to the weaponization of Congress’ oversight machinery against the investigation into Trump, furthering his assaults on our institutions and the rule of law.

What happens if Trump fires Rosenstein or makes a serious effort to remove Mueller? It is not hard to envision many GOP candidates siding with Trump as a way to energize Republican voters, thus further rallying them against the investigation and making it even less likely that GOP lawmakers intervene. In other words, the GOP’s slide into authoritarianism could get a whole lot worse.

* OFFICIAL WON’T RULE OUT MUELLER FIRING: On NBC’s “Meet the Press,” White House legislative affairs director Marc Short repeatedly said Trump has no intention of firing Robert S. Mueller III or Rod J. Rosenstein, but refused to rule it out:

“Because you don’t know how far off this investigation is going to veer. Right now, he has no intention of firing him. But we keep having the same conversation again and again and again. The president says I have no intention of firing him, but the media keeps at it every single day, every single week, ‘When’s the president gonna fire them?’ The investigation is ongoing. We’ve complied in every possible way.”

Once again, Trump actually did unsuccessfully order his White House counsel to fire Mueller, and it has been widely reported that he seriously considered firing Rosenstein.

* HILLARY CLINTON RIPS TRUMP’S ATTACKS ON MEDIA: In a speech at a festival in New York, she tore into Trump’s treatment of the press as follows:

“Today, we have a president who seems to reject the role of a free press in our democracy. Although obsessed with his own press coverage, he evaluates it based not on whether it provides knowledge or understanding, but solely on whether the daily coverage helps him and hurts his opponents.”

This is, of course, 100 percent true, but plenty of people will come up with some way of saying that she should just accept her loss and go away quietly.

* HIGH COURT TO CONSIDER TRUMP’S TRAVEL BAN: Bloomberg raises the curtain on the oral arguments the Supreme Court will hear on Wednesday over Trump’s thinly veiled Muslim ban:

The court will consider whether the travel ban’s roots lie in anti-Muslim comments Trump made during his campaign … and whether judges can second-guess the president’s national-security assessments. The case will mark the biggest test yet of Trump’s relationship with the court … The justices hinted they will uphold the travel ban when they issued an order in December letting it take full effect during the legal fight.

Let’s not forget that the “national security” rationale for this policy was badly undercut by two Homeland Security memos. Even if the court lets it stand, we all know the real reason for it.

* TRUMP’S BAN REFLECTS ‘RELIGIOUS BIGOTRY’: Robert Barnes notes that the court may defer to Trump’s broad discretion on immigration and national security. But Theodore Boutrous, a lawyer for a group of Catholic bishops, notes this:

“This case comes to the court with this backdrop of a president who has been shattering norms, even brazenly saying they don’t matter,” said Boutrous, who filed a brief … urging the court to strike down the ban. His brief said that the travel ban is a result of “blatant religious discrimination” and that it “poses a substantial threat to religious liberty that this court has never tolerated before and should not tolerate now.”

Anthony Kennedy will be interesting to watch in this regard.

* CORKER’S TEPID ENDORSEMENT OF GOP CANDIDATE: On CNN yesterday, Sen. Bob Corker was repeatedly pressed on his support for Tennessee GOP Senate candidate Marsha Blackburn. All he would say was that he’s “supporting our nominee,” while stressing that he will not campaign against Democrat Phil Bredesen, whom he described as “my friend.”

Corker, you may recall, has previously described Bredesen as “a very good mayor, a very good governor, a very good business person.” And this has alarmed top Republicans.

* BREDESEN WILL MAKE IT A REAL RACE: Dave Weigel sums up the state of the Tennessee Senate race right now:

Democrats have not won a statewide race in Tennessee since Bredesen’s 2006 reelection and have not won a Senate race since 1990 … But early polls in Tennessee have found Bredesen leading Blackburn. As of their last fundraising reports, the congresswoman had $5.9 million to spend and Bredesen had $1.7 million.  But the former governor has raised enough to keep the race on the radar, and Blackburn, who gained national prominence during the rise of the tea party movement, is running to Corker’s right.

If Democrats can somehow win in Tennessee, their path to a majority (via Nevada and Arizona) becomes more plausible.

* WE ARE UNPREPARED FOR FUTURE RUSSIAN SABOTAGE: The Post has a good editorial running through all the ways we are unprepared for the next round of Russian electoral sabotage. It flows from the top:

The surest way to secure the nation’s elections is to deter attacks in the first place. … But Mr. Trump undercut the message last week when he demanded the rollback of … promised sanctions, which were planned in response to a suspected chemical attack by the Russian-backed Syrian regime. Further reports about Mr. Trump’s continuing fixation on appeasing Mr. Putin may lead the Russian government to believe that it would face few serious consequences for again interfering in U.S. elections.

Not to mention that Trump has said numerous times the initial Russian sabotage never happened at all.