Voters in Florida and Arizona are set to vote on Tuesday in what are likely to be some of the most contentious primaries of the season.

In Arizona, Rep. Martha McSally Martha Elizabeth McSallyThe Hill's Campaign Report: Presidential polls tighten weeks out from Election Day Mark Kelly: Arizona Senate race winner should be sworn in 'promptly' New ABC/WaPost poll finds Trump edging Biden in Arizona, Florida MORE is facing two conservative firebrands, former state Sen. Kelli Ward and former Maricopa County Sheriff Joe Arpaio, in a bitter Republican primary for the seat of retiring Sen. Jeff Flake Jeffrey (Jeff) Lane FlakeHow fast population growth made Arizona a swing state Jeff Flake: Republicans 'should hold the same position' on SCOTUS vacancy as 2016 Republican former Michigan governor says he's voting for Biden MORE (R).

In Florida, all eyes will be on the Republican and Democratic gubernatorial contests, as well as a trio of House primaries that Democrats are eyeing in their quest to retake the House in November.

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At the same time, Oklahoma is holding a series of runoff elections to pick the Republican nominee for governor, as well as nominees from both parties in four of the state’s five House districts.

Here are the key races to watch on Tuesday:

Bitter GOP brawl divides conservatives in Arizona

McSally has emerged as the front-runner in a three-way race to replace Flake that has deeply divided the state’s conservative base.

To win, McSally, a favorite of the GOP establishment, has had to pivot hard to the right, particularly on issues like immigration and her support for Trump.

Notably, President Trump Donald John TrumpSteele Dossier sub-source was subject of FBI counterintelligence probe Pelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Trump 'no longer angry' at Romney because of Supreme Court stance MORE has yet to endorse any of the Republicans in the race, given all three candidates have personal connections to Trump.

But two-term congresswoman McSally has recently begun to set her sights on the general election, where she will likely face presumed Democratic nominee Rep. Kyrsten Sinema (D-Ariz.).

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The Arizona Senate race, considered a "toss-up" by The Cook Political Report, is expected to be one of the blockbuster contests in November as Democrats aggressively target the seat.

The Republican winner will have some catching up to do. The bitter, contested primary has distracted the candidates, allowing Sinema ample space to get her message out.

Sinema, the three-term Democratic congresswoman, has consistently held a lead over likely winner McSally in polls tracking the hypothetical match-up between the two candidates.

Democrats also brawl in heated Arizona House race

In running for Senate, McSally has sparked another heated race — in the Democratic primary to replace her in the House in November.

Former Rep. Ann Kirkpatrick Ann KirkpatrickArizona Rep. Tom O'Halleran wins Democratic primary Arizona Rep. Ann Kirkpatrick wins Democratic primary Cook shifts 20 House districts toward Democrats MORE (D-Ariz.) is vying to win in Arizona’s 2nd District, having relocated after previously representing the state's vast 1st District in the House.

But the move has opened her up to intense criticism by her primary challenger, former Arizona state Rep. Matt Heinz, who recently compared Kirkpatrick’s desire to get back to the House to a “meth addiction.”

Heinz has sought to put Kirkpatrick on the defensive over her more moderate past stances when she was representing the 1st District, including accusing the former congresswoman of previously opposing gun reform proposals.

Arizona’s 2nd District represents a prime pickup opportunity for Democrats: Democratic presidential nominee Hillary Clinton Hillary Diane Rodham ClintonFox News poll: Biden ahead of Trump in Nevada, Pennsylvania and Ohio Trump, Biden court Black business owners in final election sprint The power of incumbency: How Trump is using the Oval Office to win reelection MORE beat out Trump in the district by roughly 5 points in 2016, and The Cook Political Report rates the race “Lean Democratic.”

On the Republican side, four are contending to replace McSally including the head of the Tucson Hispanic Chamber of Commerce Lea Marquez Peterson, who's widely considered the front-runner.

Florida to test value of Trump’s endorsement

The power of Trump's endorsement will again be tested in Florida's Republican gubernatorial primary, where Agriculture Commissioner Adam Putnam is duking it out with Rep. Ron DeSantis (R-Fla.), who has secured the president's backing.

Putnam has been a favorite son in Florida Republican politics since he won a seat in the state House at the age of 22. But he is facing an unexpectedly aggressive challenge from DeSantis, who has closely hitched himself to Trump.

The latest polling in the race from Florida Atlantic University shows a dead heat, with Putnam leading DeSantis 32-31 percent – well within the survey’s margin of error.

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Other recent polls show DeSantis could be headed for a blowout win, with a survey by St. Pete Polls last week putting him ahead of Putnam by more than 20 points.

Trump's endorsement in the most recent GOP gubernatorial primaries has been worth its weight in gold. In Georgia, for example, Secretary of State Brian Kemp crushed Lt. Gov. Casey Cagle after getting the blessing of the president, while in Kansas, Secretary of State Kris Kobach defeated incumbent Gov. Jeff Colyer in a tight primary race that took days to be decided.

Florida's gubernatorial race to replace term-limited Gov. Rick Scott (R), who's running for Senate, is considered a "toss-up" in a state that has had a Republican governor since 1999.

Democratic crowd in race to become Florida governor

Expectations that Democrats can retake the governor's mansion in Florida have led to the emergence of a five-way primary for the party's nomination, though only three are seen as having a realistic shot.

Former Rep. Gwen Graham Gwendolyn GrahamModerate Democrats now in a race against the clock Dear Iowans: Apologies for Sen. Rick Scott's lack of decency Jimmy Buffett takes musical shots at Trump during concert MORE (D-Fla.), daughter of former Sen. Bob Graham (D), has consistently led in the polls along with former Miami Beach Mayor Philip Levine.

But Tallahassee Mayor Andrew Gillum, a progressive who has been endorsed by Sen. Bernie Sanders Bernie SandersThe Hill's Campaign Report: Trump faces backlash after not committing to peaceful transition of power Bernie Sanders: 'This is an election between Donald Trump and democracy' The Hill's 12:30 Report: Trump stokes fears over November election outcome MORE (I-Vt.), is pulling out all the stops to win the primary, taking a bus tour across Florida and bringing in a slew of high-profile surrogates, including Sanders himself.

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Those late-in-the-game efforts may be paying off for Gillum. A survey by St. Pete Polls released Sunday showed the Tallahassee mayor running in second place behind Graham, with 25 percent of the vote.

Also in the race is South Florida billionaire Jeff Greene. Once considered a top-three candidate for the Democratic nomination, Greene has seen his numbers tank in recent weeks, with the latest St. Pete Poll showing him barely clinging to double digits.

Aiming for Florida in race to retake House

Democrats are eyeing three Republican-held Florida seats in their quest to flip the 23 seats they'll need to regain the House in November.

Former Health and Human Services Secretary Donna Shalala is widely seen as a shoo-in for the Democratic nomination in the race to replace retiring Rep. Ileana Ros-Lehtinen Ileana Carmen Ros-LehtinenEx-Florida GOP congresswoman under federal investigation: report 'Trump show' convention sparks little interest on K Street Shalala to face Salazar in Florida rematch MORE (R-Fla.) in Florida’s 27th District.

But Shalala still faces primary challenges from four other Democrats: former Knight Foundation Program Director Matt Haggman, state Rep. David Richardson, former University of Miami academic adviser Michael Hepburn and Miami Beach Commissioner Kristen Rosen Gonzalez.

Clinton won Florida’s 27th District by nearly 20 points in 2016, making it a prime target for Democrats.

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The Republican race to replace Ros-Lehtinen has attracted eight candidates, including Miami-Dade County Commissioner Bruno Barreiro.

Another Democratic target is Florida's 18th District, where first-term Republican Rep. Brian Mast Brian Jeffrey MastSen. Rand Paul says he and his wife were 'attacked by an angry mob' after Trump speech Florida Republican apologizes after Facebook posts about sex, rape uncovered Most Black women since 2004 running for office this year MORE is seen as vulnerable. Mast's district went for Trump by 9 points in 2016, but former President Obama scored a narrow win there in 2008.

Mast will face two primary challengers, businessman David Cummings and physician Mark Freeman, who have both campaigned on intensely pro-Second Amendment platforms after Mast supported a series of gun control measures after the shooting at a high school in Parkland, Fla.

The winner of the GOP primary in Florida's 18th District will face whoever emerges from the Democratic primary between Lauren Baer, a former Obama State Department official, and lawyer Pam Keith.

Democrats are also eyeing another Republican-leaning seat, Florida’s 16th District. The race is seen as winnable after the current incumbent, Rep. Vern Buchanan Vernon Gale BuchananMORE (R), came come under scrutiny for purchasing a yacht the same day that the GOP passed its tax overhaul.

Buchanan faces no opponents, while on the Democratic side, attorney David Shapiro is favored to win the nomination over Jan Schneider, another lawyer who lost against Buchanan in 2016.

Both Baer in the 18th District and Shapiro in the 16th District have been named into the Democrats' "Red to Blue" program, providing them with fundraising and organizational support.

Oklahoma’s Republican gubernatorial race down to two

Oklahoma City Mayor Mick Cornett and Tulsa businessman Kevin Stitt emerged as the top vote-getters in a crowded Republican gubernatorial primary in June.

But neither candidate managed to crack the 50 percent of the vote needed to secure the nomination, forcing the two men into a runoff.

Current Oklahoma Gov. Mary Fallin (R) is term-limited and cannot seek reelection. A Morning Consult survey released last month gave Fallin the distinction of being the least popular governor in the country, with her approval rating tanking in the wake of a high-profile teachers’ strike.

The winner is likely to coast to victory in deep-red Oklahoma against Democratic nominee Drew Edmondson, a former state attorney general who won the party's nod in June.