He later telephoned his congratulations to the new justice, then at the rally returned to his own attack on the Democrats as "an angry left-wing mob".
The justices themselves made a quiet show of solidarity.
The demonstrators went up the steps of the Supreme Court holding signs and chanting, "we believe survivors" and "hey hey, ho ho, Kavanaugh has got to go".
Still, Kagan noted the night before that Kennedy has been "a person who found the center" and "it's not so clear we'll have that" now.
The Senate voted 50-48 in favour of confirming Brett Kavanaugh's appointment following a week of drama, including an interruption of the final vote by protesters shouting 'Shame on you!' and 'I do not consent!' Yet Kavanaugh is joining under a cloud.
In a viral video, Collins was accosted by protesters this week on Capitol Hill.
The outcome, telegraphed Friday when the final undeclared senators revealed their views, was devoid of the shocks that had come nearly daily since Christine Blasey Ford said last month that an inebriated Kavanaugh tried to rape her at a 1982 high school get-together. Hangers and worse have been delivered to their offices, a Roe v. Wade reference.
In an unexpected move on the eve of Friday's vote, retired supreme court justice John Paul Stevens said Kavanaugh's strikingly partisan tone while denying the allegations against him before the Senate judiciary committee last week should disqualify him.
Kay Coles James, president of the conservative Heritage Foundation, called the vote "a victory for liberty in America" and called Kavanaugh "a good man and good jurist". At one point in the hearing, Kavanaugh blamed a Clinton-revenge conspiracy for the accusations against him. He led Trump's commission that investigated voter fraud - ultimately failing to uncover evidence to back the President's claims. Democrats dismissed the truncated report as insufficient.
But Murkowski ultimately withdrew herself from the final tally as a gesture of goodwill toward her Republican colleague, Sen.
Republican Lisa Murkowski of Alaska, a fellow moderate and a friend of Collins, is the only Republican who has indicated she will vote no. She voted "present", balancing out Daines' absence.
Their vote, which was paired because Daines could not attend, maintains the same two-vote margin and does not change the outcome.
Maine House Speaker Sara Gideon of Freeport said in a telephone interview that she is seriously thinking about a challenge in a vote that is more than two years away.
Manchin (D-W.V.) was seen as one of the possible swing votes on Kavanaugh, but on Friday he came out as the lone Democrat to support President Trump's pick for the high court.
However, the Manchin, Collins and Flake coalition would be enough to confirm Kavanaugh if they actually follow through on how they are saying they are going to vote.
Vice-President Mike Pence planned to be available Saturday in case his tie-breaking vote was needed, which now seems unlikely.
But Democrats hope women angered at the Kavanaugh accusations will turn out in large numbers to vote out Republicans.
"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".
What was said in the Senate?