Republican Sen. Susan Collins on Sunday defended her decision to vote in favor of Brett Kavanaugh's confirmation to the Supreme Court and shrugged off concern her action could cost her her Senate seat in 2020.

'Whatever the voters decide, but I'm going to do what I think is right,' Collins said on CNN's 'State of the Union.'

She also dismissed talk of a challenge from President Barack Obama's Ambassador to the United Nations Susan Rice, pointing out Rice doesn't live in Maine.

'Her family has a home in Maine but she doesn't live in the state of Maine,' Collins said. 'Everyone knows that.'

Sen. Susan Collins dismissed talk of 2020 challenges against her

Former United Nations Ambassador Susan Rice indicated that she would consider running

Her confident tone comes as Democrats in her state expressed their anger that Collins, a key vote in the confirmation process, moved to elevate him to the Supreme Court.

Already possible contenders are exploring a challenge to her and a multi-million fundraising campaign against her is in the works.

Collins added that Rice 'pleaded' with her to give an introduction when she was nominated to be ambassador in 2009.

'The irony is that back in 2009 when she was nominated to be ambassador to the U.N., she came to me, even though I did not know her back then at all, and pleaded with me to introduce her before the committee, which I was happy to do because her family had links to the state of Maine,' Collins said.

Rice indicated on Twitter she would consider running when Collins faces voters again in two years. Rice's mother is from Maine and she spent summers there as a child.

Collins also defended her vote for Kavanaugh, who was accused by sexual assault by multiple women, which he denies.

The Republican senator took care to say she believed Christine Blasey Ford, who testified before the Senate Judiciary Committee, was attacked but she did not think it was Kavanaugh who was the perpetrator.

'I do not believe that Brett Kavanaugh was her assailant. I do believe she was assaulted, I don't know by whom, and I'm not certain when. But I do not believe he was the assailant,' Collins said.

Collins took care to say she believed Christine Blasey Ford was attacked but not by Kavanaugh

President Trump praised Collins as 'incredible'

She also expressed her displeasure for Kavanaugh blaming the Clintons for his confirmation problems. In his testimony before the Senate Judiciary Committee he argued anger at his work on Clinton's impeachment was behind the attacks on him.

Collins also said she didn't like Kavanaugh's angry response to Democratic Sen. Amy Klobuchar, when she questioned his drinking habits.

'I did believe that he should not have taken the shot at the Clintons and that in his questioning with certain senators and responding to their questions, particularly Amy Klobuchar, that he stepped over the line,' she said.

And she noted she didn't like President Donald Trump's attack on Ford.

'I felt that the president was not respectful to Dr. Ford,' she said.

She also conceded Kavanaugh probably drank too much in high school. Ford accused Kavanaugh of pinning her to a bed, trying to rip her clothes off, and covering her mouth when she screamed during a teenage party in the 1980s.

'I think that Judge Kavanaugh drank too much in high school,' Collins said on CBS' 'Face the Nation.' 'But the background investigations that the FBI conducts always have a question of 'did you drink? Did the nominee drink to excess or use drugs?' That is a standard question that's asked each and every time. And 150 people were interviewed for those background investigations and none of them brought forth evidence to support that.'

She also said former President George W. Bush called her three times to lobby her. Kavanaugh worked as staff secretary for the president

'He actually called me three times. He knows Brett Kavanaugh very well,' Collins said.

She said her decision on how to vote on Kavanaugh was one of the toughest she has ever made.

'I's certainly ranks right up there. There's no doubt about it. There have been ... very difficult decisions, but this was a tough one,' she said.

Collins on Friday gave a 45-minute speech on the Senate floor laying out her reasons for supporting Kavanaugh. Her vote was essential to his confirmation.

Trump praised her as 'incredible.'

'She gave an impassioned, beautiful speech yesterday. And that was from the heart, that was from the heart,' he said on Saturday.

But Democratic donors and political activists rallied against Collins and launched a multi million dollar bid to defeat her.

A deeply divided Senate voted on Saturday to confirm Kavanaugh to the Supreme Court, delivering a victory for Trump with a narrow 50-48 vote.

Campaigning is underway to ensure Maine Republican Senator Susan Collins (pictured) does not retain her seat in the 2020 election over her decision to support Justice Brett Kavanaugh

Collins delivered a 40 minute speech in the Senate announcing her support for Kavanaugh

Justice Brett Kavanaugh (pictured) was confirmed as the 114th Justice in a narrow vote Saturday

Dr Christine Blasey Ford accused Kavanaugh of sexually assaulting her while the two were in high school, prompting a week's delay in his confirmation to allow the FBI to conduct an investigation into the alleged incident.

Kavanaugh has denied all allegations.

Collins reviewed the results of the investigation, which included testimony from ten different witnesses but not from Ford or Kavanaugh on Friday.

She subsequently voted to advance Kavanaugh's nomination and said that she will vote yes on Kavanaugh' during the full Senate's confirmation vote on Saturday.

Recruiting efforts have now begun to ensure that Collins is defeated by whichever Democrat runs against her in the 2020 election campaign.

In the day after Collins threw her support behind Kavanaugh, a crowd-sourced effort to finance her eventual 2020 opponent raised more than $1 million.

The whopping sum brought the total amount raised to just about $3.2 million ― far more than Collins' last challenger spent in total in the 2014 midterm race.

Major donors already pledged $1 million to an effort to register and educate voters in Maine ahead of the contest, organizers told the Huffington Post.

More than 100,000 pledges were made as of Saturday afternoon, with around 30,000 of those coming in the previous 24 hours.

Jesse Graham, the co-executive director of Maine People's Alliance said: 'We're in conversations with lots of major donors over the last couple of weeks'.

'They want to make sure that everyone who is upset by this vote is actually a registered voter by 2020, and that we have resources to make sure everyone in Maine remembers how Sen. Collins voted'.

Jesse Graham (pictured) hopes his fundraising drive can ensure Collins is defeated by the opponent who runs against her in Maine in the 2020 election

She won her last two Senate elections in 2008 and 2014, with more than 60 percent of the vote.

She has a strong reputation for bipartisanship in her home state both because of her clashes with more right-wing Republicans like unpopular outgoing Governor Paul LePage, and her votes against Republican attempts to repeal Obamacare.

But the big donors funding the effort think Collins' reputation as a bipartisan crowd-pleaser is overstated after her votes for Kavanaugh, Justice Neil Gorsuch and the GOP tax law.

A major Democratic donor who is helping organize the effort said: 'There's this narrative out there about Collins being untouchable.

'And I think that's an outdated narrative, based on her running in an off year, in a pre-Trump era, against an underfunded candidate with no name ID'.

The separate crowdfunding campaign crossed the $2 million mark while Collins was delivering her speech explaining her vote for Kavanaugh.

There is already one announced challenger for Collins named Dr Cathleen London, a physician who announced her bid in July.

Maine House Speaker Sara Gideon (pictured) announced she would consider a bid after November's election, saying Kavanaugh doesn't deserve a seat on the highest court in the land

Dr Cathleen London (pictured) announced her candidacy for US Senate against Susan Collins

But Democratic operatives in Maine named several other potential challengers including Democractic Congresswoman Chellie Pingree and her daughter, Hannah Pingree, a former speaker of the state House.

Adam Cote, a lawyer and Iraq War veteran who finished second in this year's Democratic gubernatorial primary and Jared Golden, the Democratic nominee in Maine's rural 2nd District and a veteran of the Iraq and Afghanistan wars , were also touted as contenders.

Two other potential candidates expressed interest Friday. Maine House Speaker Sara Gideon wrote on Facebook she would consider a bid after November's elections.

'Women both in Maine and across the country have raised our voices loud and clear,' Gideon wrote.

'Brett Kavanaugh should have no seat on the highest court in the land. Unfortunately, Senator Collins has chosen to vote against the interests of us all. Maine deserves a champion in the US Senate'.

The crowdfunding project, which had an average donation of $28.40, was organized by the Maine People's Alliance, Mainers for Accountable Leadership and progressive activist Ady Barkan.

The funds will sit in an escrow account until her opponent emerges, Barkan told the Huffington Post.

Collins denounced the fundraising drive, saying she considered the 'quid pro quo fundraising to be the equivalent of an attempt to bribe me to vote against Judge Kavanaugh'.