The 2022 Missouri Senate GOP primary is heating up with the state’s attorney general, a former governor, a local celebrity and two sitting members of Congress vying for a seat held by the GOP since 1987 – in a race seen partly as a political test of loyalty to former President Trump.

"We’re winning, and we're winning by a lot," former Gov. Eric Greitens told Fox News.

Greitens, who has called his supporters "MAGA Fighters," wants to continue Trump’s challenge against the Republican establishment — even vowing to push for ousting Senate Minority Leader Mitch McConnell, R-Ky., from leadership if elected to the Senate.

"The Republican Party must become an America First party," said Greitens. "We can’t have a RINOs who stabbed President Trump in the back."

Former Gov. Eric Greitens delivers the keynote address at the St. Louis Area Police Chiefs Association 27th Annual Police Officer Memorial Prayer Breakfast on April 25, 2018.

Former Gov. Eric Greitens delivers the keynote address at the St. Louis Area Police Chiefs Association 27th Annual Police Officer Memorial Prayer Breakfast on April 25, 2018. (Laurie Skrivan/St. Louis Post-Dispatch/Tribune News Service via Getty Images)

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Greitens, along with Missouri Attorney General Eric Schmitt, Rep. Vicky Hartzler, Rep. Billy Long and Mark McCloskey have all thrown their hats into the GOP primary race since Sen. Roy Blunt announced his retirement last March. 

Schmitt and Greitens have been seen as front-runners in early polls, though the race is far from over. 

"As I get around the state, we've got the energy on our side here of the grassroots are very supportive of the work we're doing, taking the fight to Joe Biden," Schmitt told Fox News. 

Schmitt has been leading an 11-state coalition against the Biden administration’s federal vaccine mandate — which the Supreme Court shot down as unconstitutional last November.

"I’m taking a blowtorch to Joe Biden’s radical agenda," said Schmitt. "They want a fighter, and they want a proven conservative in the Senate that's never going to quit on Missouri, and that’s my record."

The packed race is still taking shape with both familiar and unfamiliar faces. 

"The person who might be the least popular overall could win," Charlie Brennan, a 33-year-old St. Louis talk radio host, told Fox News. "Anybody has a chance, because they’re going to divide up the vote if they all remain between now and primary day." 

"You need visibility, you need money, and you need organization," Brennan added. "But, to be visible is a big key, especially when you’re in that crowded field and you’re trying to get your name out there."

Mark McCloskey, a Republican candidate for U.S. Senate in Missouri, and his wife, Patricia McCloskey, walk outside the Kenosha County Courthouse, Tuesday, Nov. 16, 2021, in Kenosha, Wisconsin.

Mark McCloskey, a Republican candidate for U.S. Senate in Missouri, and his wife, Patricia McCloskey, walk outside the Kenosha County Courthouse, Tuesday, Nov. 16, 2021, in Kenosha, Wisconsin. (AP Photo/Paul Sancya, File)

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Hartzler’s constituency has held one of the largest media markets in the state, but the congresswoman is far from St. Louis, where hot-button issues such as crime and police reform have gained national recognition. 

"My background makes me different in that I am the only person in this race who has been involved in agriculture their whole life and agriculture is Missouri’s No. 1 industry," said Hartzler, also a member of the House Agriculture Committee.

Hartzler’s campaign recently traded jabs with Long, releasing a statement to Politico: "Billy is not focused on fighting for Missouri, he’s just looking for his next big meal."

"If they’re going to get me for being fat, I’ve got them right where I want them," Long told Fox News. "You can tell they’re worried, but they don’t answer the question about why her scores are so terrible on the conservative scales."

Long has also been razor-focused on securing Trump’s endorsement, touting his several trips to visit the former president at his resort in Mar-a-Lago, Florida. 

"We are in frequent communication," Long said of his relationship with Trump. "I expect that he’s going to weigh in when the time is right. He knows my record… and I’ve never wavered off the Trump train. I’m the one that originated the phrase, ‘Trump train.’"

Greitens has kept his communication with Trump very low-key, saying, "I have tremendous respect for the president and his team, and I always, always keep any communications that we have private because that’s exactly what they need to be."

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The former governor resigned from office back in 2018 following a criminal investigation into an extramarital affair, but the investigation was botched by a former FBI agent who has since been charged with seven felonies. 

"People saw what President Trump had to endure during, for example, the Trump-Russia collusion hoax, and the people of Missouri also now recognize that because I’m a fighter, the left is going to come after me," Greitens said.

Candidate Mark McCloskey, encompassing the ultimate image of a "MAGA fighter" in his famous defense of his own St. Louis home from hard-charging activists back in June 2020, told Fox News he might not support Greitens if the former governor becomes the GOP candidate. 

"That might be difficult to say at this point. You don’t know who’s going to be the Democrat. Normally, I would say I would never vote for a Democrat under any circumstances. But there are some things worse from being a Democrat sometimes," said McCloskey. 

Beyond his RNC appearance and his viral gun-toting incident, McCloskey has remained in the headlines—even suing the city of St. Louis last month to return his guns seized. But he maintains that his portfolio as a personal injury attorney and generational Republican underscore his qualifications for office.

"I didn’t need to be a politician," said McCloskey. "I believe this country is at the tipping point where if we do not win this election, this type of redemption, real independence to D.C., this country will not survive and the forces of the left, the individuals that are trying to strip us of our personal liberties, the United States government, which no longer respects the rule of law."

Trump ally Rep. Billy Long jumps into Missouri's 2022 Senate GOP primary

In this Nov. 2, 2010 file photo, then Missouri Republican Representative Billy Long speaks to supporters at an election night rally in Springfield, Missouri.  (AP Photo/Jeff Roberson)

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There is a fear among the GOP of history repeating itself—with either a tight race against a Democrat or a far-right candidate alienating many in the Republican base. 

In Blunt’s race for Senate back in 2016, he won 49.2% of the vote, to Democrat Jason Kander’s 46.4%. In addition, former Sen. Claire McCaskill, a Democrat, won her seat by 54.7% against Todd Akin back in 2012, amid Akin’s scandalous comments about rape and abortion. 

"McCaskill was successful and even supporting what was an extremist to help him get through the primary. But this is still Missouri," Rep. Emanuel Cleaver, D-Mo., told Fox News. "It’s going to be difficult. Missouri is a red state. There is a likelihood that we could get a Republican candidate with a baggage sufficient to run right down the middle, you know, ideologically and politically down to emerge a win."

Cleaver is a friend to Blunt and shares the Kansas City area with Hartzler. 

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"[What] we’re going to have to do is have a massive presidential year-like turnout. I think that’s going to give us our best chance and maybe the only chance if we have an off year turnout," said Cleaver. "If we get the same kind of turnout that we got when it was Roy Blunt was last on the ballot, Democrats could have a chance."

"People care about what President Trump thinks but they also appreciate the voting record with him," Hartzler told Fox News. "We’re in crisis right now because of the Biden administration. Missouri deserves somebody in Washington who has a track record of fighting for their values and getting things done and that’s what I have done."