Senate Minority Leader Mitch McConnell Thursday said Judge Ketanji Brown Jackson has a history of "judicial activism" he fears she'll bring to the Supreme Court – but that he won't seek to undermine her legitimacy because of it. 

"I see hallmarks of judicial activism in Judge Jackson's record. Therefore, I will vote no," McConnell, R-Ky., said Thursday morning ahead of a procedural vote on the nominee.

"We've seen over and over that when judicial activism triumphs over fidelity to the rule of law, our courts mutate, mutate into clumsy proxy battlefields for arguments that belong in this chamber and out in 50 state legislatures," McConnell said. "This is unfair to the American people. It damages our institutions, not the least the courts themselves."

photo of Ketanji Brown Jackson

Supreme Court nominee Ketanji Brown Jackson testifies during her Senate confirmation hearing on Capitol Hill, March 23, 2022. (AP Photo/Alex Brandon)

SCHUMER REVEALS TIMELINE FOR FINAL VOTE ON KETANJI BROWN JACKSON SUPREME COURT CONFIRMATION

The Senate is expected to vote to officially confirm Jackson sometime Thursday afternoon, marking a major victory for President Biden and Democrats. Jackson will replace retiring Justice Stephen Breyer, who said when he announced his retirement earlier this year that he will step down at the end of the Supreme Court's current term. 

But despite their reservations about her, McConnell said Republicans will accept the fact that Jackson will soon be seated on the Supreme Court for life. 

MURKOWSKI AND ROMNEY SUPPORT BIDEN NOMINEE KETANJI BROWN JACKSON FOR SUPREME COURT

"Top Republicans will not imply she is illegitimate. We will not call for court-packing. I won't be joining any mobs outside her new workplace and threatening her by name," McConnell said in comments directed at Democrats' behavior regarding the Supreme Court that Republicans say is dangerous. 

Mitch McConnell

Senate Minority Leader Mitch McConnell speaks to reporters after a Republican strategy meeting at the Capitol on Oct. 19, 2021. (AP Photo/Andrew Harnik)

"Democrats must stop their political siege of the institution that Judge Jackson is about to join," he said. "They must stop their assault on judicial independence. We're about to have a new justice whose fan club has openly attacked the rule of law."

SENATE VOTES TO MOVE FORWARD WITH JACKSON SUPREME COURT NOMINATION AFTER JUDICIARY COMMITTEE DEADLOCK

Jackson's confirmation will be bipartisan. Sens. Mitt Romney, R-Utah, Susan Collins, R-Maine, and Lisa Murkowski, R-Alaska, all said earlier this week that they will vote for Jackson. They said they expect to have some disagreements with the justice but that she is well-qualified for the job, and will therefore have their votes. 

photo of Ketanji Brown Jackson

Judge Ketanji Brown Jackson listens during her Senate Judiciary Committee confirmation hearing on March 23, 2022. (AP Photo/Alex Brandon)

"My support rests on Judge Jackson’s qualifications, which no one questions; her demonstrated judicial independence; her demeanor and temperament; and the important perspective she would bring to the court as a replacement for Justice Breyer," Murkowski said. "It also rests on my rejection of the corrosive politicization of the review process for Supreme Court nominees, which, on both sides of the aisle, is growing worse and more detached from reality by the year."

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All 50 Democrats are expected to back Jackson, meaning she will comfortably clear the simple-majority hurdle needed to be confirmed in the 50-50 Senate. 

Nevertheless, McConnell said, Jackson appears destined to make rulings on the Supreme Court that will infuriate Republicans and please the Democrats who pushed for her. 

"Judge Jackson will quickly face a fork in the road. One approach to her new job will delight the far left. A different approach would honor the separation of powers and the Constitution," McConnell said. "The soon-to-be justice can either satisfy her radical fan club or help preserve the judiciary that Americans need, but not both. I'm afraid the nominee's record tells us which is likely, but I hope Judge Jackson proves me wrong."