Washington (CNN) Supreme Court nominee Brett Kavanaugh wrote an op-ed for the Wall Street Journal on Thursday arguing he is an "independent, impartial judge" and conceding he "might have been too emotional" in his testimony in front of the Senate Judiciary Committee last week.

"I was very emotional last Thursday, more so than I have ever been," Kavanaugh writes in the Journal. "I might have been too emotional at times. I know that my tone was sharp, and I said a few things I should not have said. I hope everyone can understand that I was there as a son, husband and dad. I testified with five people foremost in my mind: my mom, my dad, my wife, and most of all my daughters."

Kavanaugh and California professor Christine Blasey Ford testified in front of the Senate Judiciary Committee on September 27 after Ford accused the nominee of sexually assaulting her when they were both in high school. Ford alleges a drunken Kavanaugh pinned her down at a party and attempted to remove her clothes, covering her mouth when she tried to scream. Kavanaugh vehemently denies the allegation.

Kavanaugh's last-ditch effort to present himself as an impartial judge is another extraordinary decision in a confirmation process full of unprecedented moments. It follows Kavanaugh's decision last week to sit down for an interview with Fox News ahead of the wrenching hearing where he and Ford testified, making him one of the most visible Supreme Court nominees in memory.

In his opening statement to the Senate Judiciary Committee during the hearing, Kavanaugh said he had written the monologue the previous day.

During his testimony, Kavanaugh alternated between angrily yelling at Democrats on the committee and tearing up, delivering the most heated partisan message heard from a Supreme Court nominee in modern times. He accused Democrats of creating "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, and millions of dollars in money from outside left-wing opposition groups."

It was a performance that caused lifelong Republican former Supreme Court Justice John Paul Stevens to change his views on Kavanaugh's suitability for the highest court. Stevens said Thursday that he had changed his mind for reasons that have "really no relationship to his intellectual ability or his record as a federal judge," and added that "he's a fine federal judge."

"But I think that his performance during the hearings caused me to change my mind," the retired justice said.

It also caused some consternation among key lawmakers.

Republican Sen. Jeff Flake of Arizona, a member of the Judiciary Committee and a key swing vote in Kavanaugh's confirmation, said Tuesday: "The interaction with the members was sharp and partisan, and that concerns me."

"And I tell myself, you give a little leeway because of what he's been through, but on the other hand we can't have this on the court. We simply can't," Flake said at a conference hosted by The Atlantic.

After Ford and Kavanaugh testified before the Judiciary Committee, Flake said he would not vote for Kavanaugh on the Senate floor without an FBI investigation of the sexual assault allegation made against him. Senate Majority Leader Mitch McConnell subsequently formally requested that the White House instruct the FBI to do a supplemental background check.

On Thursday, Kavanaugh sought to assuage worries about how political he might be on the court.

"The Supreme Court must never be viewed as a partisan institution," Kavanaugh writes in the op-ed in the Journal. "The justices do not sit on opposite sides of an aisle. They do not caucus in separate rooms."

He adds, if confirmed to the nation's highest court, "I would always strive to be a team player."

Kavanaugh writes he has been "subjected to wrongful and sometimes vicious allegations," and that his time in high school and college "has been ridiculously distorted." He writes his wife and daughters "have faced vile and violent threats."

"Against that backdrop," the nominee writes, he testified before the Judiciary Committee "to defend my family, my good name and my lifetime of public service."

"My hearing testimony was forceful and passionate. That is because I forcefully and passionately denied the allegation against me," Kavanaugh continues. "At times, my testimony—both in my opening statement and in response to questions—reflected my overwhelming frustration at being wrongly accused, without corroboration, of horrible conduct completely contrary to my record and character."

Kavanaugh writes his testimony "also reflected my deep distress at the unfairness of how this allegation has been handled."

"I revere the Constitution," Kavanaugh writes. "I believe that an independent and impartial judiciary is essential to our constitutional republic. If confirmed by the Senate to serve on the Supreme Court, I will keep an open mind in every case and always strive to preserve the Constitution of the United States and the American rule of law."

Democratic Sen. Richard Blumenthal of Connecticut, who also sits on the Judiciary Committee, told CNN's Anderson Cooper on Thursday that he wasn't buying Kavanaugh's attempt at casting his testimony in a different light.

"This op-ed in no way removes the issue of temperament," Blumenthal said on "Anderson Cooper 360."

"That testimony was written, carefully prepared, planned, premeditated -- not some emotional outburst," Blumenthal told CNN. "Judges are supposed to put emotions aside."

Two White House officials and a source close to Kavanaugh told CNN on Thursday night it was the Supreme Court nominee's idea to write the op-ed.

The source close to him told CNN, "He penned the op-ed because he felt like it was important for the full Senate to have before it in his own words something that sums up not just the last two weeks but the entire confirmation process and his life's record."

Asked who was the intended audience for the op-ed, the source said, "The Senate and the American people. The confirmation process is nasty and inherently political and this is someone who has been subject to the worst of it, but is also someone who can rise above. "

A senior White House official told CNN it was Kavanaugh's idea, saying the "free space" provided by the paper was a reason for doing it -- an easy way to get his intended message out.

But another White House official put it this way: "It's him calling his own play again. Not smart."