Polls have begun to close in Michigan, Missouri and Kansas, where former President Donald Trump’s immense sway over the Republican Party is once again at play in the GOP primary elections.

On the ballot Tuesday in Arizona, Kansas, Michigan, Missouri and Washington are high-profile gubernatorial, Senate and House nomination showdowns. Arizona polls will close at 10 p.m. ET and Washington's elections will end at 11 p.m. ET.

Also in the spotlight: three House Republicans who voted to impeach the then-president over the deadly Jan. 6, 2021, attack on the U.S. Capitol are fighting for their political lives as they face Trump-backed challengers; a proxy war between Trump and former Vice President Mike Pence; and a member of the so-called "Squad" of diverse, progressive House Democrats faces a primary challenge. 

Kansas voters will weigh in on abortion in the first ballot box test since the Supreme Court’s conservative majority in June overturned the landmark Roe v. Wade ruling, sending the combustible issue of legalized abortion back to the states.

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Here is what to watch.

Missouri

Trump on Monday backed "ERIC" in Missouri's high-profile and combative GOP Senate nomination race, on the eve of the state's primary.

After teasing hours earlier that he would be making an endorsement in the race, Trump declined to choose between two of the three front-runners in the primary: Missouri Attorney General Eric Schmitt and former Missouri Gov. Eric Greitens.

Instead, Trump gave his support to both of them.

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Schmitt, who has won two statewide elections in Missouri — for treasurer and later for attorney general — has made headlines over the past year and a half, filing numerous lawsuits against President Biden's administration. He has topped the latest surveys in the race.

Greitens, a former U.S. Navy SEAL who left office in 2018 amid multiple controversies, was once the clear front-runner in the primary race, but for months has been fighting allegations from his ex-wife that he abused her and their child. Greitens denies the claims.

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There is a long list of Republicans who fear that Greitens' political baggage could put what should be a relatively safe GOP seat in jeopardy come November. An anti-Greitens super PAC has spent more than $6 million this summer to run ads targeting the former governor.

The two Erics, along with Rep. Vicky Hartzler, who represents Missouri’s 4th Congressional District in the predominantly rural west-central part of the state, top a field of over 20 Missouri Republicans vying for the party’s Senate nomination, in the race to succeed retiring GOP Sen. Roy Blunt.

Among the others in the Republican race are Rep. Billy Long in the state’s 7th Congressional District in southwest Missouri, and Mark McCloskey, the St. Louis attorney who, along with his wife, grabbed national headlines during the summer of 2020 for holding guns outside their home to ward off Black Lives Matter protesters.

The winner of Tuesday's GOP primary will likely face off in November against either Trudy Busch Valentine, a philanthropist and beer family heiress, or Lucas Kunce, a former U.S. Marine who is running an aggressive populist-style campaign and who landed the endorsement of progressive champion Sen. Bernie Sanders on Monday. The two candidates are the polling front-runners in a crowded field of 11 Democratic contenders.

Missouri was once a competitive state but has trended Republican in recent decades. The winner of the GOP Senate primary will be considered the favorite in November’s general election.

Arizona

Trump and Pence are at odds in the GOP gubernatorial primary in the race to succeed term-limited Republican Gov. Doug Ducey. 

The former president is backing former TV news anchor Kari Lake, who is a strong supporter of Trump’s repeated and unproven claims that his 2020 election loss to President Biden was due to massive voter fraud. 

Pence, along with Ducey, endorsed real estate developer and Arizona Board of Regents member Karrin Taylor Robson. Trump and Pence were both in Arizona on the same day a week and a half ago, headlining competing campaign events.

Lake and Taylor Robson are the two front-runners in the GOP primary, with the winner likely facing off in November with Arizona Secretary of State Katie Hobbs, who is the leading contender for the Democratic gubernatorial nomination in the one-time red state that has become a top general election battleground between the two major parties.

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Trump, at his rally in Prescott Valley, Arizona — about 90 miles north of Phoenix — also showcased his support for venture capitalist Blake Masters in the state’s GOP Senate primary. Masters’ bid has also been backed and heavily supported by tech billionaire Peter Thiel, his former boss. The other top contenders in the race include businessman Jim Lamon, who's pumped millions of his own money behind his bid; Arizona Attorney General Mark Brnovich; and retired U.S. Air Force Maj. Gen. Mick McGuire, who until last year served as adjutant general of the Arizona National Guard.

The winner of the primary will face off in the general election with Democratic Sen. Mark Kelly, whom the GOP views as one of the most vulnerable Democratic Senate incumbents running for re-election this year.

Michigan 

Trump headlined a primary eve tele-rally for conservative commentator and former online news host Tudor Dixon, the gubernatorial candidate in Michigan he endorsed on Friday after new polls indicated her growing lead in the Republican nomination contest.

Among the other top competitors in the race to take on Democratic Gov. Gretchen Whitmer in November are businessman Kevin Rinke, a former owner of the Rinke Automotive Group, one of the nation’s oldest car dealership groups; chiropractor Garrett Soldano, who helped lead a ballot drive to repeal the law Whitmer used to issue COVID-19 restrictions; real estate broker Ryan Kelley, who was charged in connection to Jan. 6, 2021, attack on the U.S. Capitol; and retired Pastor Ralph Rebandt.

The GOP primary field shrank in early June after several candidates, including former Detroit police chief James Craig, were booted from the ballot for alleged fraudulent signatures. The shrinking of the field benefited Dixon, as did plenty of support from Michigan’s wealthy DeVos family, which includes former Trump Education Secretary Betsy DeVos. 

The Democratic Governors Association, as it has done in GOP gubernatorial primaries earlier this year in Maryland, Illinois, and Pennsylvania, is meddling.

Put Michigan First, a Democratic group that is affiliated with the DGA and supporting Whitmer, spent big bucks to run ads targeting her over police funding and claiming her plans would result in the state being "less safe" with "less cops on the street."

The DGA is not the only pro-Democratic group that’s jumping into a GOP primary in Michigan.

The Democratic Congressional Campaign Committee, the House Democrats’ re-election arm, spent six-figures to try and weaken GOP Rep. Peter Meijer of Michigan — one of the 10 House Republicans who voted to impeach then-President Trump — by pumping up John Gibbs, the Trump-backed candidate challenging Meijer.

Meijer, an Iraq War veteran who was elected to Congress in 2020, has been targeted by Trump over his impeachment vote. The former president endorsed Gibbs, a former software developer who served in the Trump administration as an acting assistant secretary in the Department of Housing and Urban Development. Gibbs is also a supporter of Trump’s repeated unproven claims that the 2020 presidential election was "rigged" due to "massive voter fraud." 

Meijer represents Michigan’s 3rd Congressional District, on the western side of the state’s lower peninsula, which the DCCC views as a competitive seat in November’s midterm elections. The latest Fox News Power Rankings rate the district as Lean Republican. House Democrats are hoping to hold onto their razor-thin majority in the chamber in the midterms, and they see Gibbs as a weaker general election candidate than Meijer.

Washington State

Meijer is not the only House Republican on the ballot on Tuesday who voted to impeach Trump.

Reps. Dan Newhouse and Jamie Herrera Beutler of Washington State are facing multiple primary challengers — including candidates backed by Trump. 

The former president last year backed Army Special Forces veteran Joe Kent as he targeted Buetler in Washington’s third Congressional District, in the southwestern corner of the state. He endorsed former police chief Loren Culp to take Newhouse in the 4th Congressional District, which covers a large swath of the central part of the state.

Washington conducts what is known as a jungle primary, in which the top two vote-getters — regardless of party affiliation — advance to the general election.

Six of the 10 House Republicans who voted to impeach Trump over the deadly attack on the Capitol by right wing extremists and other Trump supporters aiming to disrupt congressional certification of Biden’s Electoral College victory are running for re-election this year. 

One of them — Rep. David Valadao of California — was not targeted by Trump. Valadao in June won a spot in November’s general election, as he was one of the top two finishers in California’s nonpartisan primaries. Another — Rep. Tom Rice of South Carolina — lost his bid for renomination in the GOP primary in June to a Trump-endorsed and heavily supported challenger. 

The most well-known of the House Republicans to vote to impeach Trump — Rep. Liz Cheney of Wyoming — is facing multiple primary challengers, including a Trump-backed candidate, in Wyoming’s Aug. 16 primary.

Kansas

Voters in Kansas will be the first since the blockbuster Supreme Court ruling to weigh in on an abortion ballot measure, as they consider a state constitutional amendment on abortion access. The ballot measure aims to overturn a state Supreme Court decision from three years ago that ruled that the Kansas constitution protected abortion rights. If the measure passes, it would give the state legislature greater control over dictating abortion access.

Since Kansas is the first state to weigh in on the issue since the June high court decision, it is grabbing national attention as a bellwether in the state-level fights over legalized abortion.

What else we’re watching

Arizona’s GOP primary for secretary of state is in the national spotlight, as state Rep. Mark Finchem is one of the front-runners in the four-candidate field. Finchem, who is backed by the former president, is a strong supporter of Trump’s unsubstantiated 2020 election fraud claims. If he captures the Republican nomination and wins November’s general election, Finchem will become the top election official in a state where Biden narrowly edged Trump two years ago and a likely key battleground in the 2024 presidential contest.

It is member versus member in the Democratic primary in Michigan’s 11th Congressional District, in the northwestern suburbs of Detroit, where Reps. Andy Levin and Haley Stevens are facing off. Millions of out-of-state money have poured into the race, and two progressive champions — Sanders and Sen. Elizabeth Warren of Massachusetts — have endorsed Levin.

In Missouri’s St. Louis-centric 1st Congressional District, first-term Democratic Rep. Cori Bush, one of the newest members of the "Squad," is facing multiple primary challengers. The leading contender, state Sen. Steve Roberts, has repeatedly criticized Bush for her calls to defund the police.