He’s not on the ballot, but former President Donald Trump is front and center in two high-profile Republican primaries on Tuesday as voters in Nebraska and West Virginia head to the polls.

One week after Trump-backed Ohio GOP Senate candidate JD Vance came out on top in a crowded and divisive primary, thanks in large part to the former president’s recent endorsement, Trump’s continued sway over the Republican Party faces two more stiff tests in primary showdowns that have grabbed national attention.

JD VANCE WASN'T THE ONLY BIG WINNER IN OHIO -SO WAS TRUMP

In Nebraska’s three-way fistfight for the GOP gubernatorial nomination, Trump is backing Charles Herbster, a multimillionaire agricultural executive, in the race to succeed term-limited Republican Gov. Pete Ricketts. The contentious race also includes multimillionaire hog farmer and University of Nebraska Regent Jim Pillen, who is backed by Ricketts, and state Sen. Brett Lindstrom, who enjoys the support of moderate Republicans and cross-over Democrats.

Charles Herbster Donald Trump rally in Nebraska

Republican gubernatorial candidate Charles Herbster speaks while former President Donald Trump stands by at a rally in Greenwood, Nebraska, on May 1, 2022.  (Save America PAC )

Herbster, who in recent weeks has faced accusations that he sexually assaulted eight women – including a state senator – is a longtime top Trump donor and ally. The former president endorsed Herbster last autumn and held a rally with the candidate in Nebraska nine days ago.

And Trump’s prestige is also on the line in an intra-party battle between GOP Reps. David McKinley and Alex Mooney in West Virginia. The state lost a congressional seat during the once-in-a-decade congressional reapportionment, and both Republican incumbents were drawn into the same district. Trump’s backing Mooney in a race that’s partially turned into a test of the former president’s status as the most popular and influential politician in the Republican Party, nearly 16 months removed from the White House.

A WHOPPING $74.5 MILLION WAS SPENT TO RUN ADS IN THIS STATE'S SENATE PRIMARY

Trump described Herbster "a good man" at his May 1 Nebraska rally. And pointing to the allegations of sexual misconduct that the candidate has denied, the former president argued that Herbster had been "maligned."

Trump called Herbster "a die-hard MAGA champion" during a tele-rally last Thursday, and the former president charged that Pillen and Lindstrom were "Republicans in name only."

Jim Pillen

Republican gubernatorial candidate Jim Pillen speaks at the state Capitol on Jan. 18, 2022, in Lincoln, Nebraska. (AP Photo/Grant Schulte, File)

"Without the Trump endorsement, I don’t think Charles Herbster would be in the race," Ryan Horn, a Nebraska-based Republican strategist and communications consultant, told Fox News. "Even with the Trump endorsement, he hasn't been able to close the deal with voters."

Ricketts, the co-chair of the Republican Governors Association, last year tried to dissuade Trump from backing Herbster, and in the ensuing months has criticized Herbster as unfit to hold office. And Ricketts, whose wealthy family owns Major League Baseball’s Chicago Cubs, along with his father – billionaire TD Ameritrade founder Joe Ricketts – have contributed big bucks to an outside group that targeted Herbster in TV ads.

The group, called Conservative Nebraska, has concentrated its firepower on Lindstrom the past couple of weeks. 

WILL LIKELY ROE V. WADE RULING UPEND THE MIDTERM ELECTIONS?

The winner of the GOP primary will be considered the clear favorite in red Nebraska in November’s general election against state Sen. Carol Blood, who is all but certain to win the Democratic nomination for governor over a little-known candidate.

Brett Lindstrom - Nebraska

State Sen. Brett Lindstrom of Omaha speaks in Lincoln, Nebraska, Feb. 27, 2019. (AP Photo/Nati Harnik, File)

Similar to the Nebraska GOP gubernatorial primary, the Republican congressional primary in West Virginia’s 2nd District, where McKinley and Mooney are facing off, has seen plenty of attack ads on TV.

DEMOCRATIC SEN. MANCHIN CROSSES PARTY LINES TO SUPPORT GOP HOUSE INCUMBENT FACING OFF AGAINST TRUMP-BACKED RIVAL

A new Mooney ad spot touts, in what he calls "a breaking MAGA alert," that he’s the "only candidate Trump trusts to defend our values" and criticizes McKinley as a "RINO" and a "sellout." 

In the ad and on the campaign trail, Mooney attacks McKinley for voting in favor of the $1.2 trillion bipartisan infrastructure law – one of President Biden’s domestic achievements that will bring plenty of federal dollars to West Virginia, a state badly in need of infrastructure improvements. And Mooney targets McKinley for supporting the Democratic-controlled House select committee investigating the Jan. 6, 2021, attack on the U.S. Capitol by right-wing extremists aiming to disrupt congressional certification of Biden’s Electoral College victory over Trump.

Mooney told Fox News on Tuesday morning that Trump's endorsement matters in the race. "Voters understand that he endorsed me," Mooney said. "I think it makes a big difference."

CLICK HERE FOR THE LATEST PRIMARY ELECTION RESULTS FROM FOX NEWS 

McKinley in his latest ad charges that Mooney, who's currently facing an ethics investigation, is "desperate" and a "fraud."

"Mooney opposed Trump's wall four times; opposed Trump's plan to ban fentanyl from China; opposed Trump's plan for veterans," the moderator in the spot claims.

While the former president didn’t hold a rally for Mooney in West Virginia, he invited the congressman to speak this past Friday at a rally in neighboring Pennsylvania.

McKinley enjoys the backing of GOP Gov. Jim Justice. 

CLICK HERE TO GET THE FOX NEWS APP

And in an interesting twist, longtime moderate Democratic Sen. Joe Manchin, a former two-term governor with universal name ID in West Virginia, crossed party lines to star in a new ad on behalf of McKinley.

In the spot, Manchin accuses Mooney of lying about McKinley and charges "Alex Mooney has proven he's all  about Alex Mooney, but West Virginians know David McKinley is all about us."

Fox News' Jake Karalexis contributed to this report