Sen. Tim Kaine, left, listens as Republican challenger Corey Stewart gestures during the Virginia Bar Association debate at the Homestead in Hot Springs, Va. (Steve Helber/AP)

Sen. Tim Kaine and Republican challenger Corey Stewart clashed sharply on immigration, Russia and the economy Saturday in their first debate of the U.S. Senate race in Virginia but underlying it all was President Trump.

Stewart, chairman of the Prince William Board of County Supervisors, is running as a Trump acolyte who can fire up hardcore conservatives. Kaine is seeking a second term and a chance for redemption after Trump defeated Democrat Hillary Clinton with the senator as her vice-presidential pick.

Less than a week after a Helsinki news conference where Trump sided with Russian President Vladimir Putin over U.S. intelligence agencies, Stewart said it’s important for the United States to work with Russia on nuclear weapons, international terrorism and North Korea.

“We have a president who is standing up to the Russians,” Stewart said.

“Ha!” Kaine said as his supporters in the crowd laughed loudly.

Kaine said the investigation by special counsel Robert S. Mueller III should continue. He said Stewart often calls it a “witch hunt,” echoing Trump’s language.

“Frankly, it is,” Stewart said.

Asked after the debate whether he believed U.S. intelligence agencies, Stewart said that Russian interference in U.S. elections is “alleged” and that wrongdoing has not been proved despite more than a dozen indictments.

The 90-minute debate, moderated by PBS NewsHour anchor Judy Woodruff, unfolded in the ballroom of a mountain resort in rural Bath County, where voters heavily favored Trump in 2016, although he lost Virginia by five points.

Kaine has raised $18.2 million and had about $6 million cash on hand by the end of last month. Stewart raised nearly $1.1 million for his campaign and had $142,853 cash on hand.

Stewart announced he would seek a Senate seat a year ago this month on a promise to run a “ruthless” and “vicious” campaign.

On Saturday, he labeled Kaine a weak tool of the ultraleft who takes his cues from Democratic leadership and hasn’t gotten anything done as governor or senator.

A half dozen times, Kaine responded to Stewart’s criticism with the same refrain, “Make it nasty, make it personal, make it up,” eliciting boos from Stewart supporters.

Kaine ticked off a list of legislation on jobs for military spouses, federal recognition for Indian tribes, pediatric research, and career and technical training.

Picking up on Trump’s “America First” campaign slogan, Kaine called himself “100 percent Virginia First” and said he would be an independent check on the president, while Stewart is “100 percent for Donald Trump.”

On the economy, Stewart credited Trump’s tax overhaul for the low unemployment rate and soaring corporate profits.

Kaine countered that the tax cuts for individuals are small and temporary, while corporate tax cuts don’t expire.

Stewart has said he supports Trump’s immigration crackdown that separated more than 2,000 migrant children from their parents, including about a dozen minors being held at a facility in Stewart’s home district of Prince William County.

While Democrats talk about the dreams of people who came to this country illegally as children, Stewart asked, what about those of legal immigrants like his wife, Maria, who is Swedish.

“Corey’s answer was all about pitting immigrants against citizens. . . . We are a nation of immigrants,” Kaine said as several people in crowd shouted, “Legal!”

Stewart’s rhetoric on immigration and dealings with white nationalists has made him radioactive for many Republican elected officials, who have yet to campaign with him.

Woodruff asked him about past associations with white nationalist Jason Kessler and Paul Nehlen, a Wisconsin candidate barred from Twitter because of anti-Semitic and racist posts.

Stewart said he doesn’t have a “racist bone in my body,” and he said he disavowed both men.

He blamed the media for failing to call on Kaine to disavow Democratic House candidate Leslie Cockburn, who Stewart called an “open anti-Semite.”

Kaine said that Cockburn co-authored a book critical of Israeli foreign policy but that that doesn’t make her an anti-Semite.

Through a spokeswoman, Cockburn said the claims of anti-Semitism are a baseless attempt to “distract from Stewart’s hateful rhetoric” and noted that she has been endorsed by the liberal Jewish group J Street PAC.

Stewart then accused Kaine of calling conservatives who support Trump and want to protect Confederate monuments and remove “dangerous criminal illegal aliens” racists.

“That’s absolutely wrong,” Kaine interjected.

“I’m not done. People are tired of it. They’re sick of it and, frankly, that is why President Trump defeated you and Hillary,” Stewart said to applause.

Kaine challenged Stewart for skipping a winter 2017 supervisors meeting to campaign in Alabama for then-Senate candidate Roy Moore after he was accused of initiating a sexual encounter with a teenage girl when he was 32.

Stewart blamed “the left wing and the media” for assuming Moore was guilty.

He also repeatedly accused Kaine, a member of the Senate Armed Services Committee, of voting against military pay raises, housing allowance increases and expanding the Navy.

“I support the military with my own flesh and blood,” Kaine said. He paused and continued with a shaky voice: “My boy is an infantry commander in the Marine Corps.”

After the debate, Kaine said he voted in January against a stopgap budget measure that included military funding. The move led to a three-day government shutdown that at the time Kaine said he hoped would amp up the pressure to finalize a budget.

Woodruff noted that Stewart and Kaine grew up about 150 miles apart in Minnesota and asked them to name their favorite Virginian.

Stewart at first said he loved all Virginians and when pressed to pick one, he named his wife, who is on vacation with their sons.

Kaine named his 94-year-old father-in-law, Linwood Holton, a Republican who was governor in the early 1970s and integrated Virginia public schools. Kaine is married to one of Holton’s daughters, former state education secretary Ann Holton, who sat in the front row.

When the debate started, Republican Donald Barden and his wife of 32 years, Democrat Kathleen Barden, sat together. By the end, they were on opposite sides of the room.

“My Christianity is what makes me vote Democrat,” she said. “Aren’t we supposed to lift up the downtrodden?”

His response: “It takes all kinds to run a world, I suppose.”