WATCH: MSNBC's Rachel Maddow offers Brett Kavanaugh an important piece of advice

MSNBC's Rachel Maddow on Wednesday offered Supreme Court nominee Brett Kavanaugh an important piece of advice — from his own past.

In a 2015 address to the Catholic University Law School that became infamous for his claim that "what happens at Georgetown Prep stays at Georgetown Prep," Kavanaugh also offered some wisdom on the importance of being a non-partisan jurist.

"Let me run through what I think a judge as umpire means," the nominee said in 2015. "First, and probably most obviously, not being a political partisan. You have to check those political allegiances at the door when you become a judge. You have to shed them."

"It's very important at the outset for a judge who wants to be an umpire to avoid any semblance of that partisanship of that political background or that background they might have had in a particular line of work," he added. "That's the first probably most fundamental thing for a judge who wants to be an umpire."

That speech, Maddow noted, "is Brett Kavanaugh's own standard for what the fundamentals are of a judicial temperament."

She then contrasted it with his angry performance before the Senate Judiciary Committee on September 27, playing a clip of the nominee accusing Democrats of making up the sexual assault allegations brought by multiple women who knew him in high school and college.

"Whether or not that display from Brett Kavanaugh at his confirmation hearing is unnerving to you or not in terms of what you expect from a Supreme Court justice, number one, it very violates his own explicit way for how a judge should behave, for what constitutes judicial temperament," Maddow said. "And number two, the way that he behaved seems now to be bugging even some Republican senators."

Watch below, via MSNBC: