Less than five months remain before the United States holds its midterm elections, which are key to determining control of Congress — and the success of President Donald Trump’s final two years in office.

Primaries are currently under way to determine which candidates will represent their political parties in the final round of voting.

On Tuesday, three more states will head to the polls for primary races: Utah, Maryland and New York.

Joining them for a run-off election will be South Carolina, which saw several of its June 9 primary races result in a split field, with no single candidate receiving a majority of 50 percent or more.

As a result, the top two candidates in those races are headed to a showdown on Tuesday to determine who will advance to November’s midterms.

What are the biggest races to follow this week? Here’s a breakdown of some of the nail-biters.

In Utah, a potential breakthrough for Democrats

• When does voting in Utah start? Voting in many locations starts at 7am local time on Tuesday (13:00 GMT).
• When does voting in Utah end? Voting in many locations closes at 8pm local time on Tuesday (02:00 GMT on Wednesday).
• What’s one big race to watch? The Democratic primary for the 1st congressional district.

Redistricting has played an outsized role in this year’s primary races, in part due to efforts from President Trump. The Republican leader has sought to redesign state congressional maps to give his party an advantage in the race to control the House of Representatives.

But something different has happened in Utah.

In the mountainous western state, known for its rust-coloured ridges and dramatic stone arches, a battle has been playing out between voters and lawmakers over who should draw the congressional map.

Back in 2018, voters approved a ballot measure that would set up an independent redistricting commission, tasked with creating a map free of partisan gerrymandering.

Republicans in Utah’s legislature, however, voted to repeal that ballot measure, and they imposed their own map in 2021. That sparked a lawsuit, and in 2025, a court ruled that the state must use a map that does not carve up its most populous county, Salt Lake.

Splitting Salt Lake County, a Democratic-leaning area, among Utah’s four congressional districts would have diluted the power of left-leaning voters in the area.

With the new map, Salt Lake County stays largely together, giving Utah its first Democratic-leaning district since 2021. Currently, all four of Utah’s districts have Republican representatives.

That puts all eyes on the race for Utah’s first congressional district, which encompasses Salt Lake County.

The Republican nominee for the district is already selected for November: Riley Owen, a former Navy Reserve intelligence officer who worked as a White House staffer under Trump.

But Democrats are facing a four-way race to select their nominee. Polling in the lead is Ben McAdams, a former mayor of Salt Lake City and the last Democrat to represent Utah in Congress.

He is facing stiff competition, though, from state Senator Nate Blouin, a progressive who has made mitigating climate change and bringing down housing costs a top priority.

But there’s an added wrinkle: The Democratic race in Utah is an open primary, meaning that any voter, regardless of party affiliation, can participate.

State election officials have observed that a large number of ballots have been requested for the Democratic primary in Utah’s first district, more than four times the usual rate.

That has led many observers to speculate that Republicans and independents may be flooding the polls to participate — and sway the Democratic race in a way favourable to their interests.

In Maryland, a backlash against a failed redistricting push

• When does voting in Maryland start? Voting starts at 7am local time on Tuesday (11:00 GMT).
• When does voting in Maryland end? Voting closes at 8pm local time on Tuesday (00:00 GMT on Wednesday).
• What’s one big race to watch? The Democratic primary for Bill Ferguson’s state Senate seat

Normally, state legislature races get overshadowed by national-level politics. Not so this Tuesday in Maryland.

One of the most heated races on the primary ballot has to do with state Senator Bill Ferguson, a former teacher who serves as the president of the Maryland Senate.

Ferguson is currently in his third term as state senator, an office he has held since 2011. For the last six years, he has led the chamber, as well.

But as he runs for a fourth term on Tuesday, he is facing a rare campaign from a fellow Democrat to knock him out of office.

The competition centres on a decision Ferguson made last year, amid a battle to redraw congressional districts.

Last June, news emerged that President Trump was pressuring state lawmakers in Texas to redesign their congressional map to give Republicans a bigger advantage in this year’s midterms. Texas complied and passed a new map designed to help Republicans win five more seats in the US House of Representatives.

That triggered a nationwide redistricting push, with Democrats and Republicans alike pushing state lawmakers to approve new maps that would give either party an advantage to gain seats.

The stakes are high. Currently, the House of Representatives has a 218-member Republican majority, compared with 212 Democrats. A handful of wins or losses could make the difference between Republicans preserving their majority — or losing it.

Democratic proponents of the redistricting effort warn that their voters could be disenfranchised if they do not try to counteract the Republican gerrymandering with similar actions of their own.

But opponents warn of a slippery slope, where the power of citizens’ votes is diluted for party aims.

Maryland is considered a Democratic stronghold, and it has eight congressional districts: seven held by Democrats, and one held by a Republican.

Democratic leadership saw that one Republican seat as vulnerable, and many top officials, including Governor Wes Moore, pushed to redistrict the state.

But Ferguson rejected the effort. “First, let me acknowledge that nationwide, we are in a fight for democracy and that redistricting is at the core of this fight,” he wrote in an October letter.

But, he warned, redrawing Maryland’s congressional districts risked creating a scenario where a lawsuit might overturn a Democratic-drawn map, leaving the courts in charge of creating a new one.

“The legal risks are too high, the timeline for action is dangerous, the downside risk to Democrats is catastrophic, and the certainty of our existing map would be undermined,” Ferguson said.

Ferguson is still weathering the backlash to that decision. For the first time in recent years, he is facing a primary challenger, Bobby LaPin, a Baltimore progressive who has criticised Ferguson for failing to “stand up and protect” local voters, particularly in the redistricting fight.

In South Carolina, Trump waffles over endorsements

• When does voting in South Carolina start? Voting opens at 7am local time on Tuesday (11:00 GMT).
• When does voting in South Carolina end? Voting closes at 7pm local time on Tuesday (23:00 GMT).
• What’s one big race to watch? The Republican primary run-off for South Carolina’s governor

South Carolina already held its primary vote earlier this month, on June 9. But because some races were so tight, the state is holding a set of runoffs this Tuesday.

That was the case for the Republican primary to replace outgoing Governor Henry McMaster. Having served as the state’s executive since 2017, McMaster has reached his term limit, leaving an opening for another Republican leader to take control of the southern, coastal state.

South Carolina generally leans rightward, though it has pockets of Democratic-leaning jurisdictions. No Democrat has held the governor’s mansion since 2003.

But a crowded field of well-established Republicans in the June 9 primary meant that no single candidate received more than 50 percent of the vote, thus launching a run-off.

The top two vote-getters were state Attorney General Alan Wilson and Lieutenant Governor Pamela Evette, who received 26.1 and 28.9 percent of the primary vote, respectively.

Evette, however, had a major advantage going into the first round. On May 29, less than two weeks before the primary, she had been endorsed by President Trump.

“She never wavered, never let me down, and was the only South Carolina Gubernatorial Candidate to Endorse me as soon as I launched by 2024 Presidential Campaign,” Trump wrote in a gushing Truth Social post.

“Pam has my Complete and Total Endorsement — SHE WILL NEVER LET YOU DOWN!”

But it appears as if Trump himself may have wavered in his support of Evette. On Friday, Trump posted a follow-up message, endorsing both Evette and her run-off challenger, Wilson.

“I love the Wonderful State of South Carolina for every reason in the book, including the fact that it is ‘loaded up’ with truly GREAT people and Political Leaders,” Trump wrote.

He then made the case for why both Evette and Wilson deserved to win.

“These were the two that I was hoping would get into a Runoff, and they did,” Trump continued. “I can’t hurt one of them by only Endorsing the other, so, therefore, I am going to Endorse, for Governor of South Carolina, both Pam Evette and Alan Wilson!”

Critics, however, have viewed Trump’s latest post as a way for the Republican president to hedge, after some gubernatorial candidates he backed failed at the ballot box. By endorsing both, observers believe Trump is trying to neutralise any criticism he might receive, should his favourite lose the primary race.

In New York, a congressional race to replace Jerry Nadler

• When does voting in New York start? Voting starts at 6am local time on Tuesday (10:00 GMT).
• When does voting in New York end? Voting closes at 9pm local time on Tuesday (01:00 GMT on Wednesday).
• What is one big race to watch? The Democratic primary for New York’s 12th congressional district.

This midterm election season will see a wave of old-guard leadership leave Congress.

That includes party stalwarts like top House Democrat Nancy Pelosi from California and top Republican Senator Mitch McConnell.

Among the long-serving Democrats exiting at the end of this year is Representative Jerry Nadler, 79, who has represented parts of New York City in the US House of Representatives since 1992.

News of his impending retirement last September has spurred one of the most dynamic House primary races of the year.

Eight Democratic candidates are vying to replace Nadler in Tuesday’s primary for New York’s 12th congressional district, which comprises a well-heeled chunk of central Manhattan. They form an eclectic field.

One is a former Republican activist, 62-year-old George Conway, whose wife worked in Trump’s first administration. He has since rebranded as a Democrat, after clashing with Trump over what he considers abuses of power.

Another is Jack Schlossberg, a scion of the politically powerful Kennedy family. The 33-year-old writer and social media personality is the grandson of the late President John F Kennedy, and this is his first political campaign.

Other top contenders include two members of the New York State Assembly: Alex Bores and Micah Lasher.

The 44-year-old Lasher has been campaigning on his long political resume, including his work as a chief aide to Nadler and a top municipal official in New York City, where he worked alongside former Mayor Michael Bloomberg, one of his biggest donors.

The 35-year-old Bores, meanwhile, has made regulating artificial intelligence a primary tenet of his platform. Technology entrepreneurs have responded by investing millions of dollars in either supporting or attacking his campaign, using the race as a miniature battlefield for their priorities.

Polls show a tight race, and it is unclear which candidate may emerge as the Democratic nominee for November’s midterms.