The presidential primary season might be winding down, but further down the ballot, the latest primary clashes are still bringing front and center this cycle's elephant in the room: President Trump.

Across three states, Alabama, Maine and Texas, voters are weighing in on primaries in some of this year's most highly anticipated races that could ultimately tip the scales for control of either the U.S. Senate or House. And in an array of these mid-summer contests, Trump looms large.

In the Alabama Republican Senate primary runoff, a battle between scoring the president's backing and vigorously aligning with his agenda is coming to a head. For Maine Sen. Susan Collins, one of the most endangered Republicans in the Trump era, her toughest re-election yet is about to officially get a rival. And in Texas, two Democrats are tangling over the Senate nomination to take on the president's ally, Sen. John Cornyn, and help put the state in play for former Vice President Joe Biden at the top of the ticket.

Beyond the Senate, a slate of key races across the House battlefield, some of which are where Democrats are eyeing pickup opportunities to expand their current 40-seat majority in the lower chamber, will also be settled.

As voters head to the polls on Tuesday, particularly in Alabama and Texas, where runoffs will finish out a primary season that began in March, voting will look far different than it once did pre-pandemic.

Here are five things to watch for:

The end of Jeff Sessions' comeback?

In the deep south, former U.S. Attorney General, Jeff Sessions, is competing in Senate primary runoff to mount his comeback to politics after his stint in the Trump administration.

In his last Senate race in 2014, Sessions was uncontested, gliding to victory. But then, during his tenure in Trump's White House, he recused himself from the Russia probe, inciting a three-year grudge from his former boss, who is seeking to thwart his chances of returning to the Senate.

This time around, Sessions is locked in a tough primary with Tommy Tuberville, the former Auburn football coach who Trump endorsed in March, in a race that is all about the president.

Trump's wholehearted backing of Tuberville appears to be damaging Sessions' campaign, with Tuberville topping the field in the primary, leading in recents polls and pulling ahead in fundraising.

"This race is not about Jeff Sessions versus Tommy Tuberville. It is about Jeff Sessions versus Donald Trump," Angi Stalnaker, a GOP strategist in the state, told ABC.

But Sessions isn't ready to give up on his tenuous relationship with Trump, instead seeking any opportunity to showcase his pro-Trump agenda, tout Trumpian policies and remind voters that he was the first senator to back the president during the 2016 campaign.

In the final days, he's focused heavily on casting himself as an outsider to Washington. Even after Trump renewed his endorsement of Tuberville over the weekend and called Sessions a "disaster," Sessions replied, "I’ve taken the road less travelled. Not sought fame or fortune. My honor and integrity are far more important than these juvenile insults...Alabama does not take orders from Washington."

Susan Collins' challenger set to be picked on Tuesday

With a more than two-decade career in the U.S. Senate, Susan Collins, the last New England Republican in either chamber of Congress, is now fighting for survival of her political life - even though her opponent has yet to be nominated.

On Tuesday, voters will have their say in statewide primaries that were initially scheduled for June 9 but were postponed by about a month due to the coronavirus.

In the Democratic primary, Sara Gideon, the two-term speaker of Maine’s House of Representatives who’s been a state lawmaker since 2014, is widely considered the frontrunner to face off against Collins. But first, Gideon must beat out two other candidates – attorney Bre Kidman and businesswoman Betsy Sweet.

Throughout the primary, she’s been competing in a general election campaign, spending more time contrasting herself with the sitting senator than her primary competitors.

For the senior senator from Maine, who is one of the most vulnerable Republicans up for re-election in the fall, the ramifications of her controversial vote to confirm Trump’s second Supreme Court justice, Brett Kavanaugh, and a pursuit of a fifth term in the Trump era in a state carried by Hillary Clinton in 2016 are roiling her chances. Maine is one of only two states to split its electoral votes among congressional districts, but Trump lost statewide by 2.9 percentage points, while carrying the 2nd Congressional District four years ago.

The political environment has been completely transformed, one where Collins' disposition is increasingly out of step with elected leaders and voters, and her more recent voting record continues to be leveraged against her.

Still, Collins is not going down without a fight - touting her legislative achievements on the coronavirus response and underscoring what her campaign views as her likely opponent's lack of action on the pandemic since the Maine House has been out of session since March 17.

Texas Democrats' tangle over nomination to take on Cornyn

M.J. Hegar and Royce West, the two Democrats tangling over the Senate nomination to take on the state's senior senator, John Cornyn, and finish what Beto O'Rourke almost achieved, have been at sharp odds in the lead up to Tuesday's primary runoff election.

Both are defining the race as a measure of experience, with Hegar pitching her outsider status as a former combat veteran, and West elevating his decades-long career in the state Senate to make the case to voters.

"I believe we need people with the right experience representing us in D.C.," Hegar said in an interview, before adding what appeared to be a veiled swipe at her runoff rival. "I think we had an overrepresentation of career politicians and attorneys and we need more combat veterans who understand the cost of war."

"Look at my resume," West said in an interview. "Democrats are tired of being victims of history. ... We can make history by electing me as the next United States senator from the state of Texas. And not just because I'm African American, but because I've readied myself for this time in history to represent the Democratic Party in Washington."

Hegar was favored to win the primary back in March, but landed in a runoff with West after failing to secure more than 50% of the vote. She finished in first with 22%, just ahead of West's 15%, and is still considered the front-runner, as the top fundraiser in the race, who has the backing of the national Democratic establishment.

It will ultimately be a tall order to oust Cornyn, a three-term Senate veteran who secured Trump's endorsement early and has a formidable war chest.

Still, Democrats eager to put the state in play this cycle, after years of holding out hope that finally the battleground will turn blue, view Cornyn, who has tethered himself to the president in the hopes of being buoyed by the the pro-Trump flank, as out of touch with voters in fast-changing Texas.

"Texas is ready to lead," Hegar said. "We don't want to be thought of as the state that has kids in cages. We're ready to lead in immigration reform. We're ready to lead on health care reform because Texas even before the pandemic was in a health care crisis."

House battlefield takes shape in Texas suburbs

In a state that could offer Democrats some of the biggest payoffs, the party is looking to a slew of congressional districts across the Texas suburbs to expand their offensive front for the fall -- as the outskirts of cities, that were once the bedrock of the GOP's support, drift away from the party under Trump.

In the Houston suburbs, both the 10th and the 22nd Congressional Districts offer Democrats an opportunity to make inroads after two nearly successful challenges against GOP Reps. Michael McCaul and Pete Olson.

In the race against McCaul, Mike Siegel, a civil rights attorney and the 2018 Democratic nominee, is seeking a rematch to represent the district, which also stretches to the Austin suburbs, but only if he can defeat Dr. Pitesh Gandhi in the runoff.

In the Republican runoff to replace Olson, who is retiring, Troy Nehls, the Fort Bend County sheriff, is squaring off against Kathaleen Wall, a GOP donor who is using most of her own millions to fund her bid and tethering herself to Trump after coming in second in March. But waiting on the other side of Tuesday is an expected tight race, after Olson faced a surprisingly tight challenge from Sri Kulkarni, a Democrat, who came within 5 percentage points in 2018, and is the Democratic nominee again this year.

One of the seats most primed for Democrats to take come November is the 23rd congressional district, which sits along the U.S.-Mexico border and covers parts of the San Antonio and El Paso suburbs, after GOP Rep. Will Hurd announced he was not seeking re-election. His retirement has left two Republicans, Tony Gonzales and Raul Reyes Jr., fighting for the nomination.

Trump has already intervened in the primary, lining up behind Gonzales, but on Monday, his campaign waded in deeper, sending a cease-and-desist letter to the Reyes campaign for a "misleading" mailer that features the president, suggesting Trump backed him. The eventual Republican nominee will ultimately face Democrat Gina Ortiz Jones, the 2018 congressional candidate who lost to Hurd by less than one percentage point, and is the Democratic nominee this cycle.

In the suburbs of Dallas, Democrats are aiming to loosen the GOP's grip on the 24th Congressional District, after the retirement of Rep. Kenny Marchant. But the Democratic primary runoff is shaping up to be a battle over credentials, with Kim Olson, who ran for agriculture commissioner in 2018, leaning heavily into her experience as a retired Air Force colonel, and Candace Valenzuela, a local school board member, tapping into the energy of the nationwide protests over racial inequality to underscore why her candidacy is ready to meet the moment. She would be the first Afro-Latina in Congress.

For Republicans, one primary stands out as a test of the weight of the president's endorsement, reflecting the central fight at heart of the Alabama Senate race: who is Trumpier?

In Texas' 13th Congressional District, the two Republican contenders, Ronny Jackson, the former White House physician, and Josh Winegarner, an agriculture expert and lobbyist who is backed by retiring GOP Rep. Mac Thornberry, are competing over who could ultimately best serve the interests of the district, which is rated as the most Republican in the country.

Despite nabbing Trump's endorsement, which came just before the March primary, Jackson finished nearly 20 points behind Winegarner, who has been weaponizing Jackson's Washington's ties against him, running ads saying that the district is his rival's back-up plan.

Jackson contends that his personal connection to the president could boost his clout in Washington. On election eve, the president shored up last-minute support for Jackson, according to the Dallas Morning News, pitching him as a "friend" and "somebody that can help me a lot in Washington."

But in the Texas Panhandle, personal ties might not be enough.

How coronavirus changed it all

Since the onset of the coronavirus, the spring has been marred by a turbulent election season.

From Wisconsin's risky spring election, which brought long lines at the height of the state's lockdown, to Georgia's messy primary that left voters waiting for hours, after some never received an absentee ballot, to even Kentucky's mostly successful contests, state election officials have been tested by the coronavirus in unprecedented ways.

But now, a resurgence of the coronavirus across the Sun Belt and west is emerging as three more states step up to the plate to attempt voting in the middle of a pandemic. In all three, contests were delayed by the virus.

In Maine, the governor signed an executive order to expand absentee voting in the state, not requiring voters to cite a specific reason for requesting a ballot in their forms.

But in Alabama and Texas, election officials are taking an opposing path. The U.S. Supreme Court ruled earlier this month to reverse a lower court order that expanded absentee options for Alabama voters. The high court opened the door for the secretary of state to reinstate restrictions for voting, including prohibiting statewide curbside voting and requiring that voters applying for absentee ballots provide a copy of their ID and signature of two witnesses or one notary public with the ballot.

In Texas, after weeks of legal wrangling between Democrats and Republicans in the state that led all the way to the U.S. Supreme Court, Texas’ existing vote-by-mail apparatus was not expanded universally to allow for any voter to cast an absentee ballot during the pandemic. In-person voting will take place across roughly 6,600 polling locations in a state seeing a record-breaking spike of coronavirus cases, including in Houston, a hotspot.

Across all three states - at least in some of the most populous regions - safety precautions, from face coverings, to hand sanitation stations, and the like, will be in place to mitigate the spread of COVID-19.

Still, some areas are facing the same hurdles that arose in many states that preceded Tuesday's elections.

In Bexar County, which covers San Antonio and is the fourth largest in Texas, at least eight polling locations were closed due to poll worker shortages.

"There is protection for them in terms of what they try to do, but anybody can walk in without a mask," Nelson Wolff, the county judge in Bexar said, underscoring the risks of holding in-person voting amid a rapidly spreading virus. "The governor did not cover elections, and so they don’t want to work. Quite frankly, I don’t blame them."