Unless something unexpected happens, the U.S. Senate this weekend will vote by a narrow margin to confirm federal Judge Brett Kavanaugh’s appointment to the U.S. Supreme Court. It will prove to be a mistake.

In March 2017 our editorial urged the confirmation of Judge Neil Gorsuch after his selection by President Trump, noting “nothing that has been presented about his judicial background would suggest he is unprepared or unfit to take a seat on the high court.”

The same cannot be said of Judge Kavanaugh.

The demeanor displayed by Kavanaugh during the final stages of the confirmation process and his highly partisan rhetoric make him an unfit candidate for the Supreme Court. Connecticut Sens. Richard Blumenthal and Chris Murphy are making the right decision in voting against confirmation. Unfortunately, most of the fence sitters, whose final decisions proved determinative, broke in favor of confirmation.

On Friday the Senate voted 51-49 to advance the Kavanaugh nomination. Alaskan Sen. Lisa Murkowski was the lone Republican to vote against the motion. All the other undecided senators voted to move the process forward — Republicans Sens. Jeff Flake of Arizona and Susan Collins of Maine, and Democratic Sen. Joe Manchin III of West Virginia, who faces re-election in that culturally conservative state.

Later in the day, Collins confirmed she would vote in favor when the full Senate acts on the nomination.

As noted in a letter in opposition to Kavanaugh’s appointment, sent to the Senate and signed by more than 2,400 law professors, the Congressional Research Service explains that a judge requires “a personality that is even-handed, unbiased, impartial, courteous yet firm, and dedicated to a process, not a result.”

But when confronted with allegations of sexual misconduct when he was a high school student, Kavanaugh made it clear he is a man with a grudge and a score to settle.

“This whole two-week effort has been a calculated and orchestrated political hit, fueled with apparent pent-up anger about President Trump and the 2016 election, fear that has been unfairly stoked about my judicial record, revenge on behalf of the Clintons,” Kavanaugh said in his prepared remarks to the Senate Judiciary committee on Sept. 27.

He continued in this manner throughout his testimony that day, unrestrained and often inflammatory, as he interrupted and argued with senators.

“We have differing views about the other qualifications of Judge Kavanaugh,” stated the law professors in their letter to the Senate. “But we are united, as professors of law and scholars of judicial institutions, in believing that he did not display the impartiality and judicial temperament requisite to sit on the highest court of our land.”

Our editorial board agrees.

With Kavanaugh’s elevation to the Supreme Court to replace the retired Justice Anthony M. Kennedy, a jurist who would not be ideologically pigeonholed and who often provided the swing vote, any pretense of the court being above politics will be lost. The court’s validity to settle highly contentious matters depends upon public acceptance that it is more than a tool of partisan power. On such issues as reproductive rights, gerrymandering, voter protection, labor rules and environmental regulation, much of the country will conclude the fix is in. It is not a healthy situation for democracy and the rule of law.

Kavanaugh supporters have sought to excuse his performance and his allegations of vast Clinton conspiracies to block him as the result of the pressure he faced and anger he felt when confronted with what he contends were spurious allegations. But as a judge and someone who aspires to the highest court, Kavanaugh certainly should have recognized the need to remain cool. Instead he revealed his us-against-them proclivity.

Questions of honesty remain. An FBI investigation into allegations of sexual misconduct by a young Brett Kavanaugh, focused on the accounts of Christine Blasey Ford and Deborah Ramirez, failed to find corroborating evidence, according to the accounts of senators who saw it. That would not be surprising in such he-said, she-said situations.

But what else does the report say? It is being kept confidential. Did it examine Kavanaugh’s claims of never drinking to the point he did not recall his actions? It is an important point, because if he were subject to blackouts, Kavanaugh’s absolute assurances he did not act inappropriately would be suspect, while Blasey Ford’s testimony came across as credible.

This ugly affair portends more partisan fights over Supreme Court nominations to come. The nation must find some path back to normalcy or risk permanent damage to the legitimacy of the court.

The Day editorial board meets with political, business and community leaders to formulate editorial viewpoints. It is composed of President and Publisher Timothy Dwyer, Executive Editor Izaskun E. Larraneta, Owen Poole, copy editor, and Lisa McGinley, retired deputy managing editor. The board operates independently from The Day newsroom.