Originally Published: 02 AUG 22 12:08 ET

By Rachel Janfaza, Ethan Cohen and Melissa Holzberg DePalo, CNN

(CNN) -- It's primary election day in Arizona, Kansas, Michigan, Missouri and Washington.

Among the key races are GOP Senate contests in Arizona and Missouri and a member vs. member Democratic House primary in Michigan. Tuesday will once again test Donald Trump's influence on the GOP, as the former President has weighed in on several races for US Senate, governor, secretary of state and the US House, including endorsing challengers to three House Republicans who voted to impeach him last year.

Here's everything you need to know:

There are a number of high-profile races in Arizona, where Republicans will pick their nominee to take on Democratic Sen. Mark Kelly, who is seeking a first full term. The Grand Canyon state is also holding competitive races for statewide offices, including governor and secretary of state, for which the GOP primaries have become proxy fights between Trump and Arizona Gov. Doug Ducey over the future of the party.

In Kansas, the issue of abortion comes up before voters for the first time since the US Supreme Court overturned Roe v. Wade. Kansans will vote on an amendment to remove the right to abortion from the state Constitution, and a win for the "yes" vote would clear the way for the Republican legislature to pass new restrictions or a ban on abortion. Meanwhile, vulnerable Democratic Gov. Laura Kelly is seeking a second term, and former Kansas Secretary of State Kris Kobach is eyeing a third straight comeback attempt, this time running for state attorney general after losing bids for governor and US Senate the previous two cycles.

In Michigan, Republicans will pick their nominee to face Gov. Gretchen Whitmer, who is unopposed for the Democratic nomination. In the state's 3rd Congressional District, Republican Rep. Peter Meijer, who voted to impeach Trump after the January 6, 2021, attack on the US Capitol, faces a challenger backed by the former President. And in the state's 11th district, Reps. Andy Levin and Haley Stevens are both vying for the Democratic nomination in a post-redistricting primary that has become a key battleground in the party's evolving rift over Israel and the overlapping debate about Democrats' broader ideological direction.

In Missouri, the race for retiring GOP Sen. Roy Blunt's seat has attracted a crowded Republican field, including controversial former Gov. Eric Greitens. Greitens resigned from the governorship in 2018 after allegations of sexual and other misconduct, and Republicans have expressed concern that the seat could be in play with Greitens as the nominee.

And in Washington, where candidates of all parties run on the same ballot with the top-two finishers advancing to the general election, Democratic Sen. Patty Murray is running for a sixth term while Republican Reps. Jaime Herrera Beutler and Dan Newhouse, who both voted to impeach Trump, face Trump-backed opponents, among others, in their open primaries in the 3rd and 4th Districts, respectively.

How to follow CNN's election coverage

You can follow along with results on CNN.com and with our live updates. CNN's decision desk will be monitoring results and will make projections accordingly.

What time do polls close?

In Missouri, polls close at 8 p.m. ET. Mail-in ballots must be received by close of polls.

In Kansas, polls close at 8 or 9 p.m. ET, depending on time zone. Mail-in ballots must be received by the close of business on August 5.

In Michigan, polls close at 8 or 9 p.m. ET, depending on time zone. Mail-in ballots must be received by the close of polls.

In Arizona, polls close at 9 or 10 p.m. ET, depending on time zone. Mail-in ballots must be received by close of polls.

And in Washington, polls close at 11 p.m. ET. All registered voters receive a mail-in ballot. Ballots can be counted if they're postmarked by election day and received by August 15.

Election resources

CNN has numerous election-related resources available to readers:

8 things to watch in Tuesday's primaries: The final rounds of 2022 midterms primaries will come fast and furious over the next six weeks, beginning with a busy Tuesday featuring key contests around the country.

These are the election deniers on the ballot in Tuesday's primaries: Republican voters in several key swing states could select election deniers as their nominees for governorships and other top offices in primaries Tuesday.

High-stakes Senate primary tests Missouri Republicans' tolerance for an Eric Greitens return: In conversations with about 45 Missourians across the state last week, mostly Republicans, some said they were sticking by GOP Senate candidate Eric Greitens, but the majority said they had issues with the former governor.

They voted to impeach Trump. Voters in Washington state will decide whether that matters: Eighteen months removed from Donald Trump's second impeachment, has the GOP anger at party lawmakers who backed the effort subsided?

Trump's choice in Michigan gubernatorial primary faces criticism that she isn't 'MAGA' enough: The former President has thrown his support behind Tudor Dixon, a conservative commentator who has coalesced support from prominent Michigan Republicans.

These are Tuesday's key House races: House Democrats are defending their razor-thin majority with the political winds blowing largely in Republicans' favor.

Kansas set to become first state to let voters weigh in on abortion in post-Roe US: The closely watched vote offers the first popular look at voter sentiment in the wake of the US Supreme Court decision that eliminated a federal right to abortion and sent the matter back to the states.

Michigan congressman slams Democrats for meddling in his primary: Republican Rep. Peter Meijer railed against the Democratic Congressional Campaign Committee as well as some of his Democratic colleagues for defending the House Democrats' campaign arm.

With 100 days to the midterms, Democrats try to defy the odds as Republicans boast of coming wave: Democrats face broad and persistent headwinds driven by widespread gloom over the economy and President Joe Biden's consistently low approval ratings.

'What happens if they actually do win?': Democrats grapple with efforts to prop up far right candidates: The meddling by Democratic campaigns, committees and outside groups in Republican primaries has drawn criticism from across the political spectrum.

Trump-backed Arizona Senate candidate escalates election fears ahead of GOP primary: As Senate hopeful Blake Masters escalates doubts about the election system in Arizona, it's a sign of just how resonant some Republicans continue to believe election denialism is with their base.

Progressive pro-Israel group takes on AIPAC in Michigan Democratic primary fight: Reps. Haley Stevens and Andy Levin are competing for the Democratic nomination in Michigan's new 11th Congressional District.