Elsewhere on Tuesday, former Utah Gov. Jon Huntsman is locked in a tight race in his comeback bid, going down to the wire in the GOP primary against Lt. Gov. Spencer Cox. And Republicans are choosing candidates in two of Democrats’ most endangered House seats.

And after a series of election mishaps, Colorado and Utah — a bipartisan pair of states that have created mail-voting systems — get to show the rest of the country how to hold a primary in a pandemic.

Here are five things POLITICO’s campaign team is watching:

A bruised Hickenlooper seeks to right the ship

Hickenlooper entered the Senate primary a prohibitive favorite on the strength of his two gubernatorial election wins and near universal name identification. He quickly earned the endorsement of the Democratic Senatorial Campaign Committee and several candidates who dropped out of the race to back the former governor.

But the race became a one-on-one battle between Hickenlooper and Romanoff, the former state House speaker running on a platform including the "Green New Deal” and "Medicare for All," two progressive priorities Hickenlooper opposed in favor of more moderate options. Hickenlooper stumbled in the closing stretch of the campaign, incurring a less than $3,000 fine from the state’s Independent Ethics Commission dating back to his time as governor and being forced to apologize for racially insensitive comments.

Hickenlooper’s struggles unsettled the race, making it closer than most Democrats expected and giving Romanoff an opening to press his case. Republicans seized the moment, moving up scheduled TV ads to hammer Hickenlooper on the airwaves over the past several weeks, forcing Senate Majority PAC, a top Democratic outside group, to respond by backing Hickenlooper and attacking Gardner.

Hickenlooper leads Romanoff in the polls and is likely to emerge as the nominee. Despite Romanoff running to the left with support from groups like Sunrise Movement and Our Revolution, some major progressive players, including Sanders, didn’t endorse in the race. And Sens. Elizabeth Warren and Cory Booker endorsed Hickenlooper, sapping Romanoff of the national spotlight enjoyed by other recent progressive challengers.

Republicans think Hickenlooper's missteps have given Gardner an opening in one of the most challenging states for the GOP this cycle. But Democrats think Gardner’s ties to President Donald Trump — who reiterated his endorsement in a tweet Monday — combined with the state’s continued leftward shift, make it too challenging for the GOP senator to overcome. Either way, the general election in Colorado will start with a bang Wednesday.

Huntsman’s legacy at stake

In 2008, the last time Jon Huntsman was on the ballot in Utah, he won reelection with a staggering 78 percent of the vote.

But in a sign of how difficult this campaign has been, Huntsman was at only 29 percent in the last public poll of Tuesday’s GOP primary.

He still could easily win the nomination — that survey had Huntsman and Lt. Gov. Spencer Cox (30 percent) neck and neck. But after returning home from a stint in Moscow as President Trump’s ambassador to the Kremlin, Huntsman found that the state’s political culture has largely moved on.

Outgoing Gov. Gary Herbert — who was Huntsman’s lieutenant governor and took over when Huntsman resigned to become President Barack Obama’s ambassador to China in 2009 — is backing Cox, his own LG. Loyalty to Trump is a universal asset among Republicans in 49 of the 50 states, but not necessarily in Utah.

The coronavirus pandemic is also a major factor. Cases are rising in Utah: Cox is leading the state’s response, while Herbert on Monday pleaded with the Trump administration to implore the president to call on Americans to wear face coverings when out in public. The virus also hit close to the campaign: Huntsman was confined to his home for much of the past month after contracting Covid-19 and recovered only in the final days of the race.

Oklahoma showdown, Part 1

Oklahoma’s 5th District is arguably House Republicans’ best pickup opportunity in the country, but the state’s primary calendar offers Democrats a big reason for optimism. Tuesday’s primary is almost certainly heading to an Aug. 25 runoff, meaning it will be one of the last battleground seats to crown a nominee.

A massive field of nine Republicans is vying for the top two slots in this Oklahoma City-based seat, which now-Democratic Rep. Kendra Horn won by fewer than 3,500 votes in 2018’s biggest House upset. Terry Neese, a businesswoman who was the GOP nominee for lieutenant governor in 1990, is likely to nab first place, after seeding her bid with $450,000 of her own money. But there’s a three-way battle for the second spot between state Sen. Stephanie Bice, former state school superintendent Janet Barresi and businessman David Hill.

Some GOP operatives think Bice would be the most formidable; she has a natural constituency as a state senator and has proven her fundraising chops. Yet the Club for Growth has dropped money against her, airing a TV ad that linked her to disgraced movie producer Harvey Weinstein.

Regardless of which two candidates win on Tuesday, they will spend precious time and resources over the next two months in a brutal runoff. Meanwhile, Horn will be stockpiling cash. She had a war chest of $2.4 million as of mid-June.

Republicans' choice for a top Utah pickup

Rep. Ben McAdams, a moderate Blue Dog Democrat and self-described fiscal conservative, has drawn a bevy of would-be challengers. Yet recruitment flops, Trump’s sagging popularity in Mormon-heavy Utah and McAdams’ gangbusters fundraising have made his reelection prospects look stronger in this challenging district.

Four Republicans are vying to take on McAdams: former NFL player Burgess Owens, state Rep. Kim Coleman, former radio host Jay McFarland and Trent Christensen, a one-time fundraiser for Mitt Romney. The top contenders are Coleman, who has support from the political arm of the House Freedom Caucus, and Owens, who had raised nearly $640,000 by mid-June.

House Republicans faced a torturous recruitment process in Utah’s 4th District after their strongest candidate, state Sen. Dan Hemmert, dropped out unexpectedly in December. But they feel confident that the Republican lean of the district will ensure the race is competitive no matter who prevails on Tuesday.

Trump likely won’t be too much of a boon. He won the district by just 7 points in 2016 after Romney won it by 37 points four years earlier.

Mail-election states have their day in the spotlight

Most primaries held since the beginning of the pandemic have been marred by very public failures, from hourslong lines to voters’ complaints about not receiving requested absentee ballots.

Two states expected to avoid a lot of that mess? Colorado and Utah.

Both states are universal vote-by-mail states, where every voter in the state is mailed a ballot, pandemic or not. But there have still been some adjustments to make due to the pandemic.

In Utah, results may not be finalized for days, if not weeks, if any of the races are particularly close. Ballots that are postmarked by Election Day can be received up until shortly before the official canvass of results, so races that aren’t close may not be immediately called.

“Having a close race and having to wait a little for results is not unusual,” said Justin Lee, Utah’s director of elections, citing the close race in the midterms in the 4th District. Results won’t start being posted until midnight Eastern Time.

In Colorado, ballots must be received by 9 p.m. Eastern/7 p.m. Mountain on Election Day, regardless of when they're postmarked, meaning Tuesday night’s results will be much more definitive than Utah. But increased safety protocols for poll workers due to Covid-19 could slow counting a bit.

“It’s going to take a little longer to count the ballots,” said Paul López, the clerk in Denver, told The Colorado Sun. “But that doesn’t mean it’s not secure.”