RENO, Nev. (AP) — Democrats in Nevada have two open congressional seats to defend in November, and Tuesday's primary voting set the stage for what could be some of the most expensive, hard-fought House races in the country.

Republican Danny Tarkanian, son of legendary UNLV basketball coach Jerry Tarkanian, and Democrat Susie Lee, a Las Vegas philanthropist, captured their parties' nominations in southern Nevada's 3rd District, where incumbent Democratic Rep. Jacky Rosen advanced to face GOP Sen. Dean Heller in what promises to be one of the most important races for the U.S. Senate.

Former one-term Reps. Steven Horsford, a Democrat, and Cresent Hardy, a Republican, also prevailed to set up a rematch in the 4th District. It stretches from north of Las Vegas through four rural counties in the western battleground state that Democrat Hillary Clinton carried in her loss to President Donald Trump in 2016.

Both House seats will be up for grabs in November and could play an important role in Democrats' hopes of cutting into GOP majorities in Congress.

Fourth-term Rep. Mark Amodei fended off a GOP primary challenge from badly outspent tea party favorite Sharron Angle in northern Nevada's 2nd District, and Democratic Rep. Dina Titus cruised to a lopsided victory in her bid for a fifth term in the heavily Democratic 1st District in Las Vegas.

Both incumbents will be heavy favorites in the fall.

In the sprawling 2nd District where no Democrat has won since the district was created in 1980, Clinton Koble — an Obama-era appointee to the U.S. Agriculture Department who picked up labor endorsements— defeated five other candidates.

Republican Joyce Bentley, a former Las Vegas real estate agent, won her primary in the 1st District, topping Fred Horne, who finished third in the primary two years ago.

Horsford, an ex-state lawmaker from Las Vegas, became the first African-American to represent Nevada in Congress when he won the seat in 2012.

Hardy, another former legislator from Mesquite, defeated him in 2014 then lost in 2016 to Democratic Rep. Ruben Kihuen, who announced early this year he would forgo a re-election bid amid allegations of sexual misconduct.

The two former congressmen wasted little time setting their sights on the November election, blasting each other's records in the U.S. House within an hour of being declared primary winners.

"This November, Nevadans will have a choice between decency, civility and solutions or an NRA-endorsed shill for Donald Trump," Horsford said. "We cannot afford a congressman who voted against commonsense background checks to stop criminals, the mentally ill and suspected terrorists from obtaining deadly weapons ... and has voted to strip health care away from millions of Americans."

Hardy said the only person who was disappointed when "the people of Nevada fired" Horsford four years ago was "his mentor," former Democratic Sen. Harry Reid.

"The last thing Nevada needs representing them in Congress is a professional politician who cashed in on public service for massive lobbying contracts and mansions in the Washington suburbs," Hardy said.

Tarkanian and Lee each raised well over $1 million in their primary campaigns.

Tarkanian — who had won three previous GOP primaries, but lost five general elections — lost to Rosen in 2016 by fewer than 4,000 votes in the 3rd District, which covers much of suburban Las Vegas.

He launched a combative primary bid to knock off Heller, but bowed out of the race in March under pressure from President Trump and others, and announced his candidacy for what promises to be the costliest congressional race in Nevada this fall.

Lee, a fundraiser for education and disadvantaged women, lost in the 2016 primary to Kihuen in the neighboring 4th District. She has been endorsed by former Vice President Joe Biden and has financial backing from environmentalists, labor unions, women's and abortion rights groups.

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