RALEIGH, N.C. — North Carolina’s primary will be the official starting gun for one of the country’s most closely watched U.S. Senate campaigns, likely pitting former Democratic Gov. Roy Cooper against former Republican National Committee Chairman Michael Whatley.

Each candidate is the most high-profile contender for their party’s nomination, which should be sealed on Tuesday. Scores of other races also are on the ballot, including for the U.S. House, state legislature and judicial seats.

North Carolina, a traditional battleground where Democrats have been able to hold the governor’s seat even as voters helped send President Donald Trump to the White House, is one of three states kicking off this year’s midterm elections, along with Texas and Arkansas. Tuesday’s slate of primaries comes against the backdrop of the U.S. and Israel attack on Iran.

The war, which began over the weekend, has killed at least six U.S. service members, spiraled into a regional confrontation as Iran retaliated and sent oil and natural gas prices soaring. The president, who campaigned on an isolationist “America First” agenda and went to war without authorization from Congress, faces mounting questions over its rationale and an exit strategy.

North Carolina’s election this year could be crucial for determining which party controls the U.S. Senate, where Republicans currently have the majority. The seat is open because Sen. Thom Tillis decided to retire after clashing with President Donald Trump. Political experts say a typhoon of outside money could make the race the most expensive Senate campaigns in U.S. history, perhaps reaching $1 billion.

Many Democrats see Cooper, who served two terms as governor and has been successful in state politics for decades, as the party’s best shot at victory. Democrats need to pick up four seats to take back control of the Senate, and they view the most likely path as winning in North Carolina, Maine, Alaska and Ohio.

Cooper faces five lesser-known rivals on Tuesday. Other Republicans on the Senate ballot include Navy officer Don Brown and Michele Morrow, who was the party’s nominee for state schools chief in 2024.

Cooper formally entered the race weeks after Tillis announced last summer he wouldn’t seek a third term, as did Whatley, who was buoyed by Trump’s backing when the president’s daughter-in-law Lara Trump declined to enter. The two candidates have been campaigning for months against each other with little focus on intraparty opposition.

Whatley promises to keep pushing Trump’s agenda if elected, one that he says has cut taxes and spending and restored U.S. military might.

“It’s very important for us to have a conservative champion and for President Trump to have an ally in the Senate,” he said while voting early in Gastonia. “We’re going to be fighting for every family and every community in North Carolina.”

Some primary voters say Congress needs Democratic control as a counterweight to Trump and what they consider disastrous policies.

“I think we need to send a message. And I think the more Democrats that show up, and the more independents that show up for this midterm election, and the more seats we can take from the Republicans, the more he might get the message,” said Lisa Frucht, 67, said as she cast a ballot for Cooper at an early voting site north of Raleigh.

Republican voter Gary Grimes, who chose Whatley, said Democratic control of Congress could lead to more impeachment efforts against Trump that ultimately won’t succeed.

“It’ll be a repeat of what they did to Trump in the first term,” said Grimes, 71, “And they can’t see anything except getting Trump, at any cost.”

A Democrat hasn’t won a Senate race in North Carolina since 2008. Meanwhile, Cooper, 68, hasn’t lost a North Carolina election going back to first running for the state House in the mid-1980s, leading to 16 years as attorney general and eight as governor through 2024.

Whatley, 57, previously worked in President George W. Bush’s administration, for then-North Carolina Sen. Elizabeth Dole and as an energy lobbyist.

Cooper and his allies have centered campaign attacks on Whatley’s allegiance to the president and Trump policies, saying he backs higher tariffs and Medicaid spending reductions and must take blame for slow Hurricane Helene recovery aid.

Voting recently in Raleigh, Cooper said he wants to “make sure that I’m a strong, independent senator who can work with this president when I can, stand up to him when I need to and recognize that people are struggling right now.”

Whatley, Trump and other Republicans have blistered Cooper on criminal justice matters, accusing him of promoting soft-on-crime policies while governor. They’ve repeatedly highlighted last August’s fatal stabbing of Ukrainian refugee Iryna Zarutska on a Charlotte light-rail train. Trump identified Zarutska’s mother in attendance at last week’s State of the Union address.

Cooper told reporters recently that his career is about “prosecuting violent criminals and keeping thousands of them behind bars.”

Tuesday’s election also includes primary elections in all but one of North Carolina’s U.S. House districts. They include a five-candidate GOP primary in the northeastern 1st Congressional District, which is currently represented by Democratic Rep. Don Davis, who faced no primary opposition.

The Republican-controlled General Assembly created last fall a more right-leaning 1st District to join Trump’s multistate redistricting campaign ahead of the 2026 elections to retain the House. Davis won in 2024 by less than 2 percentage points.