Corrections & Clarifications: An earlier version of this story misstated Rep. Jared Golden’s district.. He represents Maine’s 2nd District.
On Tuesday, voters in four states will head to the polls to choose candidates for congressional and state primaries who will compete in battleground elections this fall.
The results of close races in Nevada and Maine could determine which party controls the Senate and House next year and which party will have the greatest influence over the policies of the winner of the presidential election in 2024. In Republican-heavy territories, contests in South Carolina and North Dakota are almost certain to determine the winner of the general election.
Here are some of the most competitive and influential races taking place across the country on Tuesday.
South Carolina
Republican Rep. Nancy Mace is facing a tough primary against former South Carolina Cabinet secretary Katherine Templeton in South Carolina’s 1st Congressional District, in what is shaping as a proxy war between former President Donald Trump’s MAGA wing of the Republican Party and the conservative establishment.
Prepare to vote: See who’s running for president and compare their positions on key issues with our Voter Guide
It will also feature one of roughly 20 Republicans who have been mentioned as possible running mate for Trump.
Mace has come under criticism from Republicans for voting with seven other House Republicans to remove then-Speaker Kevin McCarthy (R-Calif.) from his position in 2023. McCarthy supported Mace when he first ran for House office in 2020, but the Charleston-area Republican argued that McCarthy broke his promises.

The McCarthy-aligned group, the Alliance for American Prosperity, ran ads against Mace, and McCarthy’s political action committee, Majority Committee PAC, donated $10,000 to Templeton’s campaign.
Templeton, who served as state Department of Health and Environment director under then-Gov. Nikki Haley, has received endorsements from former House Speaker Newt Gingrich and Rep. Joe Wilson, R.C.
Mace, meanwhile, has been endorsed by both President Trump and House Speaker Mike Johnson, but it’s unclear how much Trump support he will receive in his coastal district, where he won the South Carolina Republican presidential primary but lost in the first round.st The district was won by Hailey by more than 20 points.
Polls in late May had Mace leading Templeton by double digits, but if he doesn’t get more than 50% of the vote on Tuesday, the race will go to a runoff.
Nevada
The balance of power in the U.S. Senate hangs in the balance in several key races in November, including for first-term Democratic Sen. Jacky Rosen’s Nevada seat.
Democrats currently hold a slim 51-49 majority in the Senate, but a race like Rosen’s could well give Republicans the potential to pull off an upset.
Rosen is expected to win Tuesday’s primary election against program manager Troy Walker and former California tax commissioner Mike Schafer.

The Republican race sees retired U.S. Army Captain Sam Brown facing off against Jeff Gunter, a former ambassador to Iceland during the Trump administration, and former Nevada Rep. Jim Marchant.
President Trump posted his endorsement of Brown on Truth Social on Sunday, a move that raised eyebrows because he did not make the announcement in person at his Las Vegas rally the same day. The Republican National Senatorial Committee and Nevada Gov. Joe Lombard have also endorsed Brown.
The Nevada primary will also feature a number of competitive House races.
In the 3rd Congressional District, in the southern tip of the state bordering California, seven Republicans are running against three-term Democratic Rep. Susie Lee. Nevada Treasurer Daniel Schwartz is one of the most closely watched candidates in the race, along with former state Sen. Elizabeth Helgelien, policy analyst Drew Johnson and composer Marty O’Donnell.
Just north, Air Force veteran David Flippo is challenging North Las Vegas Mayor John Lee for the Republican nomination.Number District. Lee, a former Democrat who switched parties in 2022, has received endorsements from Trump and Lombard. The winner of the Republican matchup will face off against three-term Democratic Rep. Steven Horsford.
Maine
In Maine’s 2nd Congressional District (which covers the northern half of the state), two Republicans are challenging three-term Democratic Rep. Jared Golden, one of just five Democrats representing a district won by Trump in the 2020 election.
The Cook Political Report rated the November race as a 50-50 contest.

The Republican candidates, Austin Theriault and Mike Soboleski, are both first-term state legislators. Theriault, a 30-year-old former NASCAR driver, has received endorsements from President Trump and Speaker Johnson and is likely to win the Republican primary.
North Dakota
One of the biggest decisions North Dakota voters face Tuesday isn’t who will run for office, but who will appear on the state’s ballot. Voters will decide on a controversial ballot measure that would set an age limit for congressional candidates, which, if passed, would bar anyone who turns 81 in their final year in office from running.
Meanwhile, Republican gubernatorial and congressional races are almost certain to determine the winner of the general election in the heavily Republican state.
Rep. Kelly Armstrong (R.D.) is running against Lt. Gov. Tammy Miller for governor after current Republican Gov. Doug Burgum (Trump’s other running mate) announced he would not run for a third term. Armstrong has the endorsement of the state Republican Party, while Miller has Burgum’s.
Five Republicans are vying to fill Armstrong’s vacant seat, including former state Rep. Rick Becker, military veteran Alex Balazs, Public Utilities Commissioner Julie Fedorchak and former Miss America winner Kara Mundo. Balazs has won the state party’s endorsement.