Republicans will decide in Wyoming’s primaries Tuesday whether to stick with long-serving U.S. Sen. John Barrasso and the first-term congresswoman who ousted Liz Cheney two years ago, Harriet Hageman.

As in the Republican primary, Democratic candidates with no previous political experience are running for U.S. House and Senate. Unlike in the GOP contests, those two Democrats are unopposed.

Meanwhile, the primary in super-conservative Wyoming — the state that has voted for Donald Trump by a wider margin than any other — is also the first time Democrats are barred from switching party registration at the last minute to participate in the livelier Republican contest. A new law bans “crossover” registration at the polls and for three months before primary day — potentially cementing the Republican dominance that has rendered Democrats nearly extinct.

The Republican-dominated Legislature passed the law in 2023 amid GOP grumbling that Democrats changing parties skewed GOP primary outcomes.

The Republican races have been low-key affairs compared to two years ago, when Hageman took on Cheney and denied her a fourth term by a more than 2-to-1 vote margin.

Cheney lost Republican support in Wyoming as a critic of Trump in a race watched far and wide. Recruited and endorsed by the former president to run against Cheney, Hageman went on to win office handily.

She’s served on the House Natural Resources and Judiciary committees in her first term.

Now, Steven Helling is running against Hageman in part as an opponent of new nuclear power amid plans to build a sodium-cooled reactor outside Kemmerer in western Wyoming.

This is Helling’s second run for Wyoming’s lone congressional seat. In 2022, he ran as a pro-Trump Democrat. He finished a distant third in the Democrats’ three-way primary.

Barrasso is seeking a third, full term after rising to prominence in the Senate.

He is chair of the Senate Republican Conference, the third-ranking position among Senate Republicans, and a ranking member of the Senate Energy and Natural Resources Committee.

He’s been an outspoken critic of President Joe Biden’s administration’s policies on immigration, fossil-fuel development and air pollution regulations.

An orthopedic surgeon and former state lawmaker from Casper, Barrasso is challenged by Reid Rasner, a financial adviser from the Casper area.

Rasner has been campaigning on a platform similar to Barrasso’s but argues for term limits. He criticizes Barrasso’s donations from defense contractors and refusal to debate him.

Scott Morrow of Laramie is the Democratic candidate for Senate and Kyle Cameron of Cheyenne the Democratic candidate for U.S. House.

Local races of note include Cheyenne’s mayoral primary, where the five candidates challenging Mayor Patrick Collins include local library employee Victor Miller, who calls himself the “meat avatar” for a ChatGPT-based artificial intelligence chatbot he says he created and calls “VIC.” Wyoming Secretary of State Chuck Gray has said an AI candidate might not be able legally to run in Wyoming but local officials have allowed VIC, in essence, to appear on the ballot as Miller.

The top two vote-getters in the mayoral primary will face each other in the general election.

Polls statewide open at 7 a.m. and will close at 7 p.m.