LAS VEGAS — U.S. Sen. Dean Heller cruised through a five-way Republican primary race Tuesday, freeing him to prepare for a tough re-election battle that could help swing control of the Senate.

Heller is considered the most vulnerable Republican U.S. senator seeking re-election this year because he's the only one running in a state that Democrat Hillary Clinton won in 2016.

He's expected to have one of the closest races in the country this November against Democrat Jacky Rosen, who prevailed over five others in her primary race.

Rosen is a former computer programmer, software designer and president of a Henderson synagogue who narrowly won her House seat in 2016 after being recruited to run by former Democratic Sen. Harry Reid.

Heller has portrayed Rosen as an ineffective newcomer tied to polarizing figures like Reid and House Democratic leader Nancy Pelosi.

"The choice this November could not be starker," Heller said in a statement. He added that, "While we've been fighting and delivering for Nevada, the only thing Jacky Rosen has done since getting to Congress is seek a promotion."

Rosen has portrayed Heller as a flip-flopper who has cozied up to President Donald Trump.

Heller was a past critic of the president, and in 2017, Trump publicly scolded him for holding up the GOP's long-promised effort to repeal President Barack Obama's health care law. He later repaired his relationship with Trump and helped deliver a rewrite of U.S. tax laws to the president's desk.

Heller "has spent the last year letting Nevadans down by breaking his promises to protect our health care, passing a fiscally irresponsible tax bill to benefit his super-wealthy donors, and failing our Dreamers to placate his party's leaders," Rosen said in a statement. Immigrants brought to the U.S. illegally as children are commonly referred to as "Dreamers," based on never-passed proposals in Congress called the DREAM Act.

Trump reached into Nevada's Senate race in March and persuaded Heller's main challenger Danny Tarkanian to drop out and instead run for a U.S. House seat.

Heller says he didn't ask Trump for the favor.