The drama of another primary day arrives on Tuesday, and in many ways, the contests across five states that stretch from the Midwest to the West Coast encompass the themes of the election cycle.

From key tests for the progressive wing to tightropes being walked by Senate Republicans and challengers in the era of President Donald Trump, the races across Arizona, Kansas, Michigan, Missouri and Washington will showcase the dynamics at the fore of the 2020 season.

On Tuesday, voters in Arizona and Michigan, both battlegrounds, are set to finalize two key matchups in November that could determine the balance of power in the Senate. A highly competitive primary between an endangered member of the "squad" -- Michigan Rep. Rashida Tlaib -- and her formal rival, Detroit City Council President Brenda Jones, is set to come to a close in Detroit and its surrounding suburbs.

In a contentious GOP Senate primary in Kansas, Democrats' meddling and Trump's lack of intervention could possibly elevate the state to be another potential pickup opportunity for Democrats on the expanding battlefield for the upper chamber. In Missouri, progressive challenger, Cori Bush, aims to unseat long-time Democratic Rep. Lacy Clay, a 20-year incumbent, in St. Louis and its suburbs, including Ferguson.

And in the midst of the novel coronavirus, chief executives on the frontlines of the response will meet their general election opponents.

Here are five things to watch on Tuesday:

Contours of the Senate battlefield to be set

In the special election for Arizona's Senate seat -- long held by the late-Sen. John McCain, the 2008 Republican presidential nominee -- the contest is shaping up to be one of Democrats' best chances to cut their deficit in the fall and potentially tilt the majority in their favor.

Sen. Martha McSally, a first-term Republican who was appointed to the seat in 2018 by Gov. Doug Ducey, is expected to cruise to a victory in her primary on Tuesday, but she is not running uncontested. Daniel McCarthy, a wealthy real estate investor, is challenging the incumbent, a sign of potential cracks in McSally's efforts to coalesce the Republican base behind her bid.

And the hurdles for McSally are likely to only get steeper from there.

McSally narrowly lost to Sen. Kyrsten Sinema, D-Ariz., in the 2018 Senate race, and as she seeks to win the seat outright, the heavyweight battle between her and Democrat Mark Kelly, the husband of former Congresswoman Gabby Giffords, is turning into one of the most costly and contentious scuffles of the election.

Republican concerns about McSally's ability to retain her seat in the fall are increasing as she lags in the polls and money race behind Kelly. The former Navy captain and NASA astronaut has proven to be a prolific fundraiser -- easily outraising his rival by more than $16 million so far this cycle and leading by at least seven points in recent polls.

Despite her efforts to showcase her pro-Trump priorities and close ties to the president -- which her campaign previously said they view as beneficial -- she didn't get behind his recent suggestion of pushing back Election Day, a signal of the bounds of Trump's influence on Senate Republicans who are balancing tough campaigns this cycle.

Another race likely to be among the central fights on the battlefield is in Michigan, where Sen. Gary Peters -- a first-term senator who won the seat in 2014 -- is one of only two Democrats this cycle running for re-election in a state Trump won in 2016.

Peters, who formerly served in the U.S. Navy Reserve, is part of the Democrats' hope of restoring the blue wall after Trump carried the state by the thinnest of margins -- about 10,000 votes -- four years ago.

But potentially standing in Peters’ way could be John James, a former Apache combat helicopter pilot in Iraq, who is running for the Republican nomination. James is attempting a second run for the Senate after a failed bid in 2018 against Sen. Debbie Stabenow, when he lost by about seven points.

James has outpaced Peters in fundraising over four straight quarters in the campaign, bringing in $6.45 million between April and June, compared to Peters' $5.25 million, and holding an edge in total fundraising for the cycle by about $1 million.

Still, he is doing a delicate dance of putting some distance between himself and the president -- who is seeing growing unpopularity in Michigan -- without alienating Trump's loyal base of voters.

"He is trying to navigate the kind of no man's land between being sensible and being too Trumpy in today's political environment," said Jeff Timmer, a veteran GOP strategist and former executive director of the Michigan Republican Party. "You cannot afford to be too Trumpy, but then again he can't afford to get too far away from Trump either or he loses the support from Trump’s solid base."

Tuesday is set to bring an end to the primaries and an official start to what will be a closely watched general election. Three months out, polling shows Peters with a double-digit lead over James, who is also further behind Trump in his matchups with former Vice President Joe Biden -- a troubling sign for a compelling candidate as he heads into the fall.

Two different tests for progressives

Tuesday brings key tests of the strength of the progressive movement in two different forms, but both in flashbacks to 2018.

In Michigan's 13th Congressional District, which covers parts of Detroit and its surrounding suburbs, Rep. Rashida Tlaib, an outspoken, progressive freshman who is also a member of the squad, is up against a highly competitive challenger in Detroit City Council President Brenda Jones in a rematch from two years ago.

In 2018, Tlaib only defeated Jones by 900 votes in the general election primary, after Jones had defeated Tlaib in a special election to fill the vacancy left by longtime Democratic Rep. John Conyers' departure from Congress.

Tlaib eked out a win in the six-way primary in 2018, but now in a head-to-head contest with Jones, who has been endorsed by her other four 2018 primary opponents, Tlaib is receiving some support from prominent Capitol Hill allies, including House Speaker Nancy Pelosi, D-Calif., and fellow members of the squad -- Reps. Alexandria Ocasio-Cortez, D-N.Y., Ayanna Pressley, D-Mass., and Ilhan Omar, D-Minn.

Still, Tlaib is likely the most vulnerable member of the freshman group as she faces Jones, who views Tlaib's national profile as a liability and a distraction from her job in Congress and her ability to address the issues confronting the district.

About 530 miles southwest of Detroit, Democratic Rep. Lacy Clay, a fixture in Congress with a 20-year career, is once against facing a primary challenge from progressive Cori Bush, who unsuccessfully ran in 2018 for the Democratic nomination.

Bush is hoping to oust the long-time incumbent with the help of the district's African American base, but unlike other incumbents who lost to more diverse primary challengers, Clay is Black and the son of another political fixture. Clay's father, Bill Clay, represented the same district for over 30 years.

Up against a 50-year tenure between the two Clays, Bush aims to peel off a crucial bloc of voters by tapping into the zeal of the recent protests over racial inequality and turn it into political prowess.

Bush argues that Clay is ineffective and out of touch with all voters in the district.

"The question the voters must ask themselves this Tuesday is: who can better represent them in Congress? When voters ask themselves that question, I have no doubt that they will decide that Cori Bush is the answer, because I’ve been an active fighter for ALL of us my whole life," she wrote at the end of a lengthy Twitter thread on Sunday responding to some attacks on her campaign by Clay.

In 2018, Clay defeated Bush by nearly 30,000 votes, but this time around, she has more money and more national influences behind her. Bush is backed by key figures in the liberal wing of the party, including former Democratic presidential candidate, Sen. Bernie Sanders, I-Vt., and Justice Democrats.

Republican brawls define contests in the Sunflower state

In Kansas, intraparty clashes over ties to the White House are set to come to a close for Republicans in the competitive Senate primary and the race in Kansas' 2nd Congressional District.

Kris Kobach, the unsuccessful 2018 gubernatorial candidate and former secretary of state, is running a Trumpian race -- without an official endorsement -- against Rep. Roger Marshall, a doctor who represents the 1st Congressional District, in the Senate primary which has been dominated by millions in outside spending in its final weeks.

Kobach is seen as the far more riskier pick for Republicans, as Democrats eye a broader Senate map. His hardline stances on guns, immigration and voting rights appear to have the potential to alienate some voters in November, should he win the primary. According to the New York Times, internal Republican polling shows that up to 30% of GOP primary voters would cast their ballot for Democrat Barbara Bollier, a former Republican and the likely Democratic nominee, should Kobach nab the nomination on Tuesday.

Marshall, an OB-GYN and the preferred pick of the GOP establishment, is the subject of millions in attack ads from Democrat-aligned Sunflower State PAC, who have gone on the air hitting Marshall in an effort to elevate Kobach through the primary.

"When he ran for governor, he was the only Republican who ran statewide who lost. Everybody else down ballot won handily. He lost. This indicates there are a lot of people who voted for Laura Kelly and then voted Republican for the rest of the line," Nathaniel Birkhead, an associate professor of political science at Kansas State University, said of Kobach.

Trump hasn’t endorsed in this race, leaving Republicans to settle it amongst themselves. And the efforts between both Kobach and Marshall to pitch themselves as the candidate who has more fealty to Trump and Trumpism reflects a similar dynamic in nearby Tennessee, where the open Senate race set to be settled on Thursday pits Bill Hagerty, the Trump-backed former ambassador to Japan and former national finance chair for Sen. Mitt Romney's 2008 presidential campaign, against Dr. Manny Sethi, an orthopedic trauma surgeon who has garnered support from Sens. Ted Cruz, R-Texas, and Rand Paul, R-Ky., as the candidate who will be a "true conservative" that supports Trump.

Back in Kansas, Marshall pulled endorsements from highly regarded establishment Republicans, including retiring Sen. Pat Roberts, whose seat the two are hoping to fill come January, and former presidential candidate Bob Dole, a Republican from the state. He’s also got the support of the Kansas Farm Bureau -- a telling sign of where the agricultural vote may sway on Tuesday considering Roberts sits as the chairman of the Senate Agriculture Committee.

In another GOP-centric fight, Rep. Steve Watkins is facing a tough primary after being convicted of charges related to voter fraud just three weeks before the primary in Kansas' 2nd Congressional District. Watkins is accused of fraudulently voting in the Topeka City Council election, but he's claiming no wrongdoing, according to the Kansas City Star.

Days after the charges were announced, Watkins stepped down from his committee assignments, which is required of U.S. House members convicted of a felony pending their charges. Watkins was previously endorsed by Trump, and in 2019, was announced as the honorary state co-chair of Trump's re-election campaign. He also still has the backing of House Minority Leader Kevin McCarthy.

Watkins’ most serious challenger is Kansas State Treasurer Jake LaTurner, 32, who upon his appointment in 2017 became the youngest statewide official in the United States.

"LaTurner is sort of a rising star in the Kansas establishment," Birkhead said. "The party never wanted Watkins anyway you can look at the campaign finance reports to kind of get the sense of that."

LaTurner is endorsed by current Rep. Ron Estes of the 4th district and Kansans for Life, who had endorsed both Watkins and LaTurner in the primary, but rescinded their endorsement of Watkins after his conviction.

Ultimately, Tuesday’s primary could end with Kansans picking two risky general election candidates, Kobach and Watkins, although both seats currently hover in likely red territory in November.

Further down-ballot, Joe Arpaio fights for political survival, Missouri aims to be 38 on Medicaid expansion

In the Republican primary for Maricopa County, Arizona, sheriff, Joe Arpaio, 88, is running again and facing an uphill climb to reclaim the seat he held for two decades until 2016.

In a three-way race against Jerry Sheridan, his former chief deputy, and Mike Crawford, a police officer from Glendale, Arpaio is looking to win by campaigning on restoring his hardline immigration stances, the very issue that put him in legal jeopardy before Trump pardoned him. But if Arpaio loses, it could signal that Arizona's all-important Maricopa County is moving away from his forceful law-and-order approach, which is aligned with Trump's own platform.

The winner will face current Democratic Sheriff Paul Penzone in November, who toppled Arpaio in 2016.

Beyond candidates on the ballot on Tuesday, voters across Missouri will weigh in on a crucial ballot initiative.

Missouri voters will decide whether to become the 38th state to expand Medicaid eligibility, possibly joining 37 other states and the District of Columbia that have already expanded the government-run health care program to cover low-income adults.

The ballot measure in a state that backed Trump by nearly 20 points, could be a blow to his administration and state Republicans, since if approved, it will expand Medicaid under the Obama-era Affordable Care Act after Republicans in the state legislature refused to broaden the program.

The measure would expand Medicaid to 230,000 low-income adults, according to supporters, by allowing adults who are between the ages of 19 and 65, whose incomes are at or below 138% of the federal poverty level to be eligible.

Since 2017, five states have voted to expand Medicaid by a ballot initiative in the Trump era. This measure is a key test for the health care debate amid the coronavirus pandemic, and less than 100 days until Election Day, which is likely to be a referendum on Trump's and state leaders' response to the public health crisis.

Fights for the governor's mansion in era of COVID-19

In Missouri and Washington, crowded gubernatorial primaries will soon turn into low-key general election matchups, but both races come as chief executives continue to combat the rampant outbreak -- testing the virus' political impact.

After the downfall of former Missouri Gov. Eric Greitens, who resigned in 2018, Mike Parson, then the lieutenant governor, assumed office.

Now, Parson is up against a crowded primary to win the seat outright, with three other candidates in the Republican race: Saundra McDowell, a former candidate for state auditor, state Rep. Jim Neely and Raleigh Ritter, a business owner. The unelected chief is expected to win on Tuesday, even as he downplays the severity of the coronavirus.

Parson has mostly stuck to a Trumpian message on the pandemic, encouraging kids to return to school, but he has also pushed for social distancing and mask wearing. Missouri surpassed 50,000 cases and is considered in the federal "red zone" for new confirmed cases, meaning it has an infection rate of more than 100 cases per 100,000 residents.

On the Democratic side, the favorite to win the primary is State Auditor Nicole Galloway, who is also facing a slate of lower-profile rivals, including Jimmie Matthews, a pastor and real estate developer, Antoin Johnson, an activist, Robin Van Quaethem, who served in the U.S. Air Force, and Eric Morrison, a pastor.

Galloway, if she topples her opponents, is expected to be a competitive challenger for Parson, but still the race is currently rated as Lean Republican.

Out west, in Washington -- a state with the first confirmed case of the coronavirus within the U.S. borders and one that was on the frontlines of the crisis throughout the spring -- there is a crowded GOP primary to take on incumbent governor and former 2020 presidential candidate Jay Inslee, who is seeking a third term.

The field of Republican challengers has narrowed in recent weeks to roughly half a dozen top contenders, including Yakima doctor Raul Garcia, who has racked up a slate of endorsements from former statewide elected Republican leaders, and Tim Eyman, a well-known conservative figure in the state having authored 11 statewide ballot initiatives that have passed since the 1990's.

Other Republicans vying to take on Inslee -- who remains popular in the state despite his unsuccessful presidential bid -- include Bothell Mayor Joshua Freed, Republic police Chief Loren Culp, state Sen. Phil Fortunato and businessman Anton Sakharov.

But Inslee, who recently put the state's reopening process on hold amid a spike in cases, is riding on high marks for his response to the crisis as he approaches Election Day. The race is rated as solidly in Democrats' corner.