(Reuters) - North Dakota Democratic U.S. Senator Heidi Heitkamp, facing a tough re-election fight, opened her debate on Thursday with Republican challenger Kevin Cramer by apologizing for a recent ad that named sex assault survivors without their consent.

Slideshow ( 2 images )

The ad, intended to highlight her support of women following the brutal debate over a U.S. Supreme Court nominee accused of sexual assault, was an untimely gaffe for Heitkamp as she struggles to hang on to her seat in next month’s election in a state that Republican President Donald Trump won by a landslide in 2016.

“Unfortunately, this week I not only disappointed many in North Dakota, I disappointed myself,” Heitkamp said. “My campaign wrongly listed many names in a campaign ad that were not authorized and not appropriate. This was a terrible mistake.”

The race illustrates the challenge Democrats face in trying to take a majority in the Senate in the Nov. 6 elections, which would require them to pick up two more seats while defending about 10 embattled incumbents, including first-term Heitkamp.

Most polls show Cramer, a three-term U.S. representative, leading the race.

After Heitkamp’s apology, Cramer seemed to see little need to go on the attack, keeping a cordial tone as the two discussed immigration, sexual assault, gun violence in schools and the impact of Trump’s trade tariffs.

Heitkamp defended her vote against Trump’s Supreme Court nominee Brett Kavanaugh, who was widely supported in the state, saying it was more important to do what she believed to be the right thing than to follow public opinion polls.

Cramer called the Kavanaugh hearings an example of mob rule, saying that the opposition to his elevation to the highest U.S. court was orchestrated to support a political agenda

“Brett Kavanaugh is a very, very good judge for North Dakota,” he said. Kavanaugh was confirmed by a 50-48 vote.

Asked about sexual violence and harassment, Cramer recommended increasing the number of female police officers and harassment training in businesses and throughout society.

“I’m not a woman, I have not been sexually assaulted. I don’t know,” he said. “But I know we can do a lot better job.”

He criticized the #MeToo movement, saying: “What we can’t have is these big movements that become political movements that undercut the integrity of the goal.”

Heitkamp attempted to tie Cramer to Republican efforts to cut social programs, including the Medicare and Social Security programs for retirees.

“When you call these programs entitlement programs, it’s an insult to every senior citizen,” she said.

For all Reuters election coverage, click: here