Senate Judiciary Chairman Chuck Grassley (R-Iowa) promised to raise $3 million to support Sen. Susan Collins (R-Maine) to counteract anger over her vote to confirm Justice Brett Kavanaugh.

"I'm going to help raise $3 million to match that," Grassley told Marth MacCallum during an interview on Fox News Tuesday, when asked what he thought of a fundraising effort against Collins in Maine that has raked in about $3 million.

Collins has come under fire from many on the left for supporting Kavanaugh in a narrow confirmation vote, who was accused of sexual assault by Christine Blasey Ford and other women.

Kavanaugh has denied the allegations, which remain uncorroborated.

GOP senators who viewed an FBI report regarding an investigation into the allegation said it showed no corroborating evidence. Senate Democrats have argued the investigation was not thorough enough.

Collins said in a speech explaining her vote on the Senate floor and in comments Sunday that she found Ford to be credible, but that there was not sufficient evidence to meet the "more likely than not" standard.

Heidi Hess, the co-director of Credo Action, told The Hill that Collins faces a "tough" reelection fight.

"She made a floor speech saying she believes survivors and saying she was going to vote against the ones who … came forward against Brett Kavanaugh, and that's not something people are going to forget," Hess said.

Former Obama national security adviser Susan Rice has said she will consider running against Collins in 2020.

Grassley fired back at accusations from liberal critics that Collins wasn't a feminist.

"That criticism is absolutely abominable," Grassley said. "She's been at the forefront of everything."

"It just goes to show you how narrow the thinking of the opposition to Kavanaugh was that they would say those extremist…positions about a person who has been with them most of the time."