A crowdfunding site where activists have been raising money to defeat Sen. Susan Collins in 2020 was inundated with pledges Friday afternoon, after the Maine Republican announced she would support Judge Brett Kavanaugh’s nomination to the Supreme Court.

By 3:55 p.m., the site had crashed, apparently overwhelmed.

"Senator Susan Collins has people more motivated than we've ever seen before," Crowdpac tweeted. "Hold tight, we'll be back shortly."

The site was back online a little less than two hours later. By Saturday morning, the campaign that vows to support Collins' future opponent had surpassed $3 million - not an insignificant amount for a political race in a state with among the smallest populations in the country (1.3 million).

A group of liberal activists began the campaign last month to pressure Collins, a key swing vote in Kavanaugh's nomination, to vote against President Donald Trump's nominee. If Collins voted no, donations would not be withdrawn from donors. If she voted yes, the pledges would fund the campaign of whoever wins Maine's Democratic nomination for the U.S. Senate in two years.

Maine People's Alliance, Mainers for Accountable Leadership and activist Ady Barkan have doubled their original goal to $4 million. The unusual fundraising effort is a sign of an energized Democratic electorate and could set the stage for Collins' re-election effort.

As the pledges poured in Friday, yet another unusual series of events in these hyperpartisan times unfolded on social media: the online crowdsourcing for a nominee and said nominee's future campaign staffers.

"Who wants to run for Senate in Maine? There will be an army of supporters with you," tweeted Jen Psaki, a former White House communications director under President Barack Obama.

"Me," Susan Rice, Obama's former United Nations ambassador and national security adviser, replied, raising a flurry of questions about what her plans are.

Rice, whose family is from Portland, Maine, later clarified, saying she's not making any announcements.

Jenna Lowenstein, a Democratic digital strategist who worked for Hillary Clinton's campaign, also said she had enlisted 75 political staffers to help elect Collins' future challenger. In a Google docs sign-up sheet she had created, Lowenstein promised to send volunteers to the eventual campaign as soon as there is one.

"Nothing like starting with binders full of women (and men) ready to take up the fight," she wrote.

A spokeswoman for Collins has sharply criticized the crowdfunding effort, calling it an attempt at extortion.

"And anybody who thinks these tactics would work on Senator Collins obviously doesn't know her. Senator Collins will make up her mind based on the merits of the nomination. Threats or other attempts to bully her will not play a factor in her decision making whatsoever," Annie Clark said in a statement before the senator announced her support for Kavanaugh.

One ethics expert told The Washington Post that the crowdfunding campaign may very well violate federal bribery statutes, which prohibit giving or offering anything of value to government officials in exchange for any acts or votes.

Marie Follayttar, co-director of Mainers for Accountable Leadership, denounced bribery accusations.

"The idea of Susan Collins attacking an effort by 35,000 small dollar donors as bribery is politics at its worst. Thousands of Mainers are trying desperately to tell her that she needs to protect abortion access and critical healthcare coverage across the country by voting 'no' on Kavanaugh," Follayttar said in a statement. "If she doesn't, we absolutely have the right to prepare to unseat her given everything Judge Kavanaugh would do on the Supreme Court to make life worse for Maine women, Mainers with pre-existing conditions and Mainers who care about fabric of our democracy. Unlike Supreme Court judges, Senators do not enjoy a lifetime guarantee of their seat; they are accountable to the people."

Collins and Sens. Jeff Flake, R-Ariz., and Joe Manchin III, D-W.Va., announced on Friday that they would vote for Kavanaugh, clearing the way for the judge to be confirmed in a narrow and largely partisan vote. One lawmaker, Sen. Lisa Murkowski, R-Alaska, broke with her party, saying Kavanaugh was a good man but “not the right man for the court at this time.”

Collins had initially expressed concerns over threats to Roe v. Wade if Kavanaugh were confirmed, effectively shifting the Supreme Court to the right for decades to come. The senator also had been among the holdout votes amid an FBI investigation into sexual assault allegations against Kavanaugh, whose nomination seemed in peril three weeks ago.

Kavanaugh inched closer to confirmation on Thursday after Collins and Flake indicated they believed the additional FBI probe had exonerated the judge.

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The Washington Post’s Seung Min Kim and John Wagner contributed to this article.