Primary elections on Tuesday night in five states will showcase some of the many factors that have been swirling around the 2022 midterm elections, including the power of endorsements, shakeups from redistricting, and the uncertain futures of the Democratic and Republican parties.
The Pennsylvania Republican Senate primary race is among the most competitive to watch. The seat, held by retiring Republican Sen. Pat Toomey, could be critical for Democrats to maintain their slim control in the Senate.
The Senate race was shaken up in late 2020 when celebrity Dr. Mehmet Oz threw his hat in the ring for the open seat. Former President Donald Trump endorsed Oz in April, saying that he would be most likely able to win the general election.
But during a rally held by Trump in Pennsylvania, some voters on the ground were skeptical of Oz, telling ABC News they did not like his changing stances on COVID vaccines, abortion and the Second Amendment.
Oz faces challengers including businessman Dave McCormick and conservative commentator Kathy Barnette, who has gained a recent surge of support.
In the days leading up to the primary, Trump came after Barnette, saying she could not win the general election. He also went after her past.
Barnette's newfound prominence also brought to light a series of Islamophobic and inflammatory comments posted to social media. ABC News has also verified images first shared by an independent researcher of Barnette marching toward the Capitol on Jan. 6, 2021. One of the videos shows Barnette walking behind a man indicted in connection with the day's events and who prosecutors described as "a self-identified member of the Proud Boys."
ABC News reached out to Barnette's campaign for comment but has not received a response. The campaign told NBC, "Kathy was in DC to support President Trump and demand election accountability. Any assertion that she participated in or supported the destruction of property is intentionally false. She has no connection whatsoever to the Proud Boys."
In the Democratic Senate primary in Pennsylvania, the three leading candidates are Lt. Gov John Fetterman, Rep. Conor Lamb and State Rep. Malcolm Kenyatta.
Fetterman served as the mayor of the small borough of Braddock, just outside Pittsburgh, for 16 years before being elected as lieutenant governor alongside Gov. Tom Wolf four years ago. He ran for Senate in 2016 but lost in the primary.
Fetterman, a progressive and the frontrunner in the race, suffered a stroke just days before Tuesday's primary -- taking him off the trail in the final stretch -- but said in a statement he expects to make a full recovery.
Kenyatta made his mark on the national stage in the summer of 2020 as a DNC keynote speaker whom the party identified as part of a group of "diverse voices from the next generation of party leaders." He was a strong ally of President Joe Biden's throughout the 2020 general election.
Lamb, who has staked out a centrist position in the primary, currently represents Pennsylvania's 17th Congressional District in the House of Representatives. He has picked up key endorsements, including from many from labor unions, in the eastern part of the state.
Then there's Pennsylvania's fierce GOP gubernatorial primary. Whoever wins the governor's race in November will also appoint a secretary of state -- the chief election officer in the state where the "big lie" and Trump's false claims that he is the legitimate winner of the 2020 election run deep.
Several candidates are vying for the GOP nomination, while Attorney General Josh Shapiro runs unopposed in the Democratic primary for governor. The races shifted dramatically in recent days when Trump endorsed state Sen. Doug Mastriano, who's attracted conservative grassroots support for his efforts to try to overturn the state's 2020 presidential result.
Mastriano attended the Jan. 6 insurrection, organizing buses to the "Stop the Steal" rally and was caught on camera walking past barricades at the Capitol ahead of the deadly protests though he has denied participating in any violence. The House Jan. 6 committee has subpoenaed him, given that he was in communication with Trump on that infamous day, but neither he nor the committee has confirmed whether he complied with the order.
In North Carolina, GOP Sen. Richard Burr announced last year he would not seek reelection. There are over 10 candidates in the race to replace him -- including the three leading candidates, Rep. Ted Budd, former North Carolina Gov. Pat McCrory and former Rep. Mark Walker.
Budd, who was endorsed by Trump, struggled earlier in the year in the polls and fundraising but now is doing better and leading in the polls.
In the Democratic Senate primary in North Carolina, former state Supreme Court Chief Justice Cheri Beasley is a front runner. If Beasley wins the general election, she could become the only Black woman to serve as a senator in the 118th Congress.
Rep. David Price of North Carolina's 4th Congressional District is retiring and a crowded Democratic field is fighting for his spot. Eight Democrats filed their candidacy paperwork, including musician and American Idol runner-up Clay Aiken. If Aiken wins the primary and the general he would become the first openly gay member of Congress from the South.
Elsewhere in North Carolina, the Republican primary for the 11th Congressional District is another hotly contested race. Rep. Madison Cawthorn, considered a right-wing firebrand in the party, has dealt with many controversies during his freshman year in Congress. On Tuesday, voters will decide if they want to keep him around. Many top GOP members have indicated that they want him gone -- including both Republican senators from North Carolina.
But on Monday, Trump -- who has endorsed Cawthorn -- took to his own social media platform Truth Social to defend Cawthorn, saying he believes that while Cawthorn made some "foolish mistakes" he deserves a second chance.
In Kentucky, leading the pack in the Democratic primary race is Charles Booker, who made a run for Senate in 2020 -- losing in the primary to Amy McGrath, who went on to compete in the general against Senate Minority Leader Mitch McConnell.
Over in Idaho, sparks have flown in the Republican primary in the race for Idaho's governor, with incumbent Republican Gov. Brad Little attempting to hold onto his position against the best efforts of his own lieutenant governor, Republican Janice McGeachin. This is the first time a sitting governor has been challenged by their own lieutenant governor of the same party since 1938.
The pair have been playing something of political cat and mouse for a few months: When Little was out of state, McGeachin has, more than once, issued anti-mask mandate-related executive orders in her role as acting governor, which Little would then rescind upon his return.
In Oregon, widely considered a blue state, there is a chance for the Republican party to make a play for the open governor's seat since term-limited Democratic Gov. Kate Brown is unpopular in the state.
In the Democratic primary for Oregon's newly redistricted 5th Congressional district, incumbent Democratic Rep. Kurt Schrader is facing intraparty controversy for keeping a key drug provision in Biden's signature Build Back Better plan from advancing.
Despite that, Schrader was the first candidate in 2022 to get Biden's endorsement, a potential indicator of how much the president wants Democrats to hold onto their seats in the House.
ABC News' Alisa Wiersema, Brittany Shepherd and Zohreen Shah contributed to this report