Five states are holding primaries on Tuesday: Nevada, Virginia, Maine, South Carolina and North Dakota. Here's what you need to know about key races in each state.

Nevada

The Democratic race for governor has been bitterly fought, and a recent poll showed the top two candidates — Christina Giunchigliani and Steve Sisolak, both Clark County commissioners — separated by only three points. Their contest has been vicious at times: Mr. Sisolak claimed in a recent ad that Ms. Giunchigliani had "single-handedly protected perverts" by weakening a sex offender bill years ago, to which Ms. Giunchigliani responded by revealing that she was sexually abused as a child.

Each hopes to be Nevada's first Democratic governor since 1999.

Attorney General Adam Laxalt is widely expected to win the Republican nomination for governor. A son and grandson of former senators, Mr. Laxalt is a supporter of President Trump and has the backing of Sheldon Adelson and the Koch brothers.

A House race worth watching is in the Third District. Representative Jacky Rosen, a Democrat, is vacating the seat to run for the Senate. It's a traditional swing district and has crowded primary fields on both sides. Among the Republican candidates is Danny Tarkanian, who agreed to run for the House instead of the Senate at the urging of Mr. Trump. That removed a primary challenge to Senator Dean Heller, who is among the most vulnerable Republicans this year. Mr. Heller is expected to face Ms. Rosen in November in one of the most competitive Senate races in the country.

[Democratic women are running for governor. Men and money stand in their way.]

Virginia

Virginia Republicans have an interesting Senate primary on Tuesday. Three Republicans are hoping to challenge the Democratic incumbent, Tim Kaine, in November: Corey Stewart, a Prince William County supervisor; Nick Freitas, a member of the Virginia House; and E.W. Jackson, a lawyer and minister.

Mr. Stewart is the best known, having narrowly lost a bitter Republican primary for governor last year, and he is leading the polls. An outspoken supporter of Mr. Trump, he has a similarly bellicose style. But he has been tarnished by his past praise for the white nationalist Paul Nehlen, as well as appearances with the organizer of last year's "Unite the Right" rally of white supremacists and neo-Nazis in Charlottesville. (He has since distanced himself from both men.)

Keep an eye, also, on the Second and 10th Districts. In the Second District, Representative Scott Taylor, a Republican, has a conservative primary challenger, and two Democrats are vying to face him as well. In the 10th District, six Democrats are seeking to challenge Representative Barbara Comstock, a two-term Republican who could be vulnerable in November.

[Here's what's coming up next on the primary calendar.]

For almost eight years, Maine has been governed by Paul R. LePage, a famously controversial Republican. Now, four candidates are jostling to be his heir apparent. But the Republican nominee may face an uphill battle, both because it is shaping up to be a strong year for Democrats nationwide and because Maine's governorship has traditionally swung back and forth.

The Democratic field is led by Attorney General Janet Mills and Adam Cote, a lawyer and longtime National Guard member. Emily's List, the national group devoted to electing Democratic women, is backing Ms. Mills and has poured $300,000 into the race.For the first time, Maine voters will use an instant runoff, or "ranked choice," system. Voters will rank the candidates in order of preference, and if no one receives a majority of the first-place votes, the last-place candidate's votes will be redistributed to his or her voters' next choices until someone breaks 50 percent. For good measure, voters will also be voting on whether to continue using ranked-choice voting.

[Learn more about Maine's instant runoff system here.]

South Carolina

Gov. Henry McMaster, who took the job last year after Nikki Haley joined the Trump administration, is facing a competitive Republican primary as he seeks his first full term. His opponents include his own lieutenant governor, Kevin Bryant, as well as Catherine Templeton, a lawyer whose website calls her a "conservative buzzsaw." While polls show Mr. McMaster ahead, it is not clear that he will break the 50 percent threshold needed to avoid a runoff.

Tight races are also expected in the First and Fourth Districts.

In the First District, Representative Mark Sanford, once expected to win re-election with little trouble, is in danger of losing to State Representative Katie Arrington, who has attacked Mr. Sanford for his criticism of Mr. Trump.

The Republican primary in the Fourth District — which is being vacated by Representative Trey Gowdy, perhaps best known for leading the House committee that investigated the Benghazi attack — is tremendously crowded, with 13 candidates.The contest between Mr. Sanford and Ms. Arrington highlights a counterpoint to the dominant trend of the 2018 midterms.

While Democrats hope to ride a wave of opposition to the president, an overwhelming majority of Republicans support him — 90 percent, according to the most recent weekly average by Gallup — and the party's anti-Trump members, like Mr. Sanford, could suffer for their stand.

North Dakota

Senator Heidi Heitkamp, a Democrat in one of the nation's most conservative states, is facing a tough re-election campaign, and her Republican challenger will be chosen on Tuesday. Representative Kevin Cramer, who holds North Dakota's only House seat, is running against Thomas O'Neill, an anti-immigration Air Force veteran. The state Republican Party has endorsed Mr. Cramer.

[For Heitkamp, a lift from an unlikely source: the Koch brothers.]

Voters will also choose Mr. Cramer's replacement in the House. State Senator Kelly Armstrong is seeking the Republican nomination against two candidates with little to no political experience: Tiffany Abentroth and Paul Schaffner. On the Democratic side, former State Senator Mac Schneider is running unopposed.

New York Times, June 12, 2018

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June 12, 2018

Post Script. 5 Primaries Today - Nevada, Virginia, Maine, South Carolina and North Dakota. Get out the vote! Pick out the strongest Democrats you can in today's primaries. That is how we win in November. #StopTrump #SaveAmerica #BlueWave2018