Senator Paul is picking a fight with President Trump over his endorsement of Congressman Mike Rogers in the Michigan Senate race, calling the candidate the “worst Deep State candidate this cycle.”

In a post on Truth Social Monday, Mr. Trump endorsed Mr. Rogers, praising him for his positions on the border, inflation, and the military, saying, “HE KNOWS HOW TO WIN.”

“Highly respected former Congressman Mike Rogers is running for the United States Senate from the Great State of Michigan. Mike has served his Country during a career loaded up with accolades and wins, from the Army to Congress, and now, hopefully, the U.S. Senate,” Mr. Trump wrote.

In response, Mr. Paul issued a string of posts lambasting Mr. Rogers and attacking Mr. Trump for his endorsement, saying, “You have to ask yourself who gives Trump this awful advice? Who’s next, John Bolton?”

“Donald Trump just endorsed the worst Deep State candidate this cycle,” Mr. Paul said. Mr. Rogers “is a never Trumper, and a card carrying member of the spy state that seeks to destroy Trump.”

Mr. Paul went on to say, “If he’s good with Mike Rogers (R-Deep State), maybe he should pick Liz Cheney for VP?” He then reposted a post from political strategist Robert Stone calling Mr. Rogers a “FRAUD.”

Mr. Rogers reportedly considered launching a presidential bid last year before deciding to endorse Mr. Trump and enter the GOP primary in Michigan. Mr. Rogers also had to move to Michigan from Florida in order to enter the primary, something on which Democrats have already seized.

“The chaotic Senate primary is getting even nastier as Trump pours gasoline on the fire. Mike Rogers abandoned Michigan a decade ago as he walked through the revolving door to get rich — and Michigan families deserve better,” the Michigan Democratic Party chairwoman, Lavora Barnes, said in a statement.

Mr. Paul isn’t the only conservative or Republican who is expressing disappointment with Mr. Trump’s endorsement. One of Mr. Rogers’s primary opponents, Congressman Peter Meijer, told the Detroit News that “you don’t respect somebody who is just kind of willing to debase themselves.”

One of the founding members of the House Freedom Caucus, Justin Amash, also expressed doubts about Mr. Rogers’s electability, saying that “when voters get ahold of the Mike Rogers receipts, they’re going to do everything they can to return him to Florida.” 

In early polling, Mr. Rogers appeared to be the frontrunner in the Michigan GOP primary, with 23 percent support, compared to Mr. Meijer’s 7 percent, and another GOP candidate, Sandy Pensler, at 2 percent. The survey of 600 likely Republican primary voters, conducted by Marketing Resource Group, found that the vast majority of respondents, 62 percent, were undecided.