(Reuters) — Voters in Pennsylvania, North Carolina, Idaho and Kentucky hold nominating primaries on Tuesday where voters will pick their parties’ candidates for the U.S. Congress and other offices, helping to shape the field for the Nov. 8 midterm elections.

Here are four contests to watch:

Mehmet Oz v. David McCormick v. Kathy Barnette

The Pennsylvania battle for the Republican U.S. Senate nomination has heated up in its final week. It features Mehmet Oz, a television wellness celebrity backed by former President Donald Trump, running against David McCormick, a wealthy former hedge fund CEO.

Adding to the complexity, conservative commentator Kathy Barnette has put in a strong closing performance and the three candidates were virtually tied in a recent public opinion poll.

John Fetterman v. Conor Lamb

With incumbent Republican Sen. Patrick Toomey retiring, Pennsylvania represents one of the best opportunities for Democrats to add to their razor-thin Senate majority, though President Joe Biden’s low approval ratings could make that difficult.

Democratic voters will choose between John Fetterman, a colorful progressive who has sought to burnish his working-class bona fides as lieutenant governor, and U.S. Rep. Conor Lamb, a centrist who currently represents a suburban Pittsburgh district in the House of Representatives.

State legislator Malcolm Kenyatta could also be a factor, after challenging Fetterman’s record on racial issues in a recent debate. Polls show Fetterman in the lead.

Pat McCrory v. Ted Budd

The contest to replace retiring Republican Sen. Richard Burr in North Carolina pits former Gov. Pat McCrory, a fiscally conservative standard-bearer of the Tea Party era, against U.S. Rep. Ted Budd, a member of the House who voted against certifying Trump’s 2020 election defeat. Trump has endorsed Budd and several opinion polls have shown him leading McCrory and 12 other candidates.

If no candidate receives 30%, a runoff will take place on July 26.

The winner of this nominating contest will likely face Democrat Cheri Beasley, a Black woman who formerly served as chief justice of the state Supreme Court. Analysts say the race could be competitive in November, though Republicans are favored.

Madison Cawthorn v. Chuck Edwards

Republican Rep. Madison Cawthorn has been a magnet for controversy since taking office in January 2021. He has been rebuked by his fellow Republicans for calling Ukrainian President Volodymyr Zelenskyy a “thug” and saying that he has witnessed cocaine use and been invited to orgies in Washington. He also faces accusations of sexual harassment and has been stopped twice for carrying firearms into airports.

State Sen. Chuck Edwards leads a field of seven Republican candidates looking to unseat him. The seat, based in the mountainous western part of the North Carolina, is considered safely Republican.

Brad Little v. Janice McGeachin

Idaho Gov. Brad Little is facing a Republican primary challenge from Janice McGeachin, who recently spoke at a political conference hosted by a white nationalist. McGeachin, who is endorsed by Trump, has been dogging Little from the right as the state’s lieutenant governor. She took the gubernatorial reins several times while Little was out of the state, issuing executive orders that banned mask mandates and ordering National Guard troops to the U.S.-Mexico border. Trump’s endorsement of McGeachin has perplexed political observers because Little is a staunch conservative who has not had public spats with Trump.

(Reporting by Andy Sullivan; Editing by Scott Malone and Alistair Bell)