If Brett Kavanaugh were part of a Supreme Court asked to weigh in on whether President Trump can avoid cooperating with the special counsel in the Russia investigation, we don’t know how he would rule.

But we do know that two decades ago, the potential future Supreme Court justice was on the prosecuting end of misconduct allegations against a president. He was a top lawyer for the Kenneth Starr-led investigation into Bill Clinton’s affair with White House intern Monica Lewinsky. And Kavanaugh was extremely critical of that president.

A 1998 memo written by Kavanaugh that was released in full Monday by the National Archives underscores his distaste for Bill Clinton’s Oval Office affair in apparently purposefully graphic terms. As the team prepared to interview Clinton, Kavanaugh advises it to put the president through the wringer “piece by painful piece” when questioning him.

If Kavanaugh had had his way, he would have asked the president nearly a dozen X-rated questions, such as this one: “If Monica Lewinsky says that you inserted a cigar into her vagina while you were in the Oval Office area, would she be lying?”

Twenty years later, the memo is almost guaranteed to be a central document in Senate questioning of Kavanaugh next month on how he would approach Trump — although Cornell Law professor Josh Chafetz warns against drawing too close a parallel between then and now. There is evidence that Kavanaugh has changed his mind on executive power. A decade after he wrote that memo, he argued in the Minnesota Law Review that criminal investigations and lawsuits against the president are “time-consuming and distracting” and ultimately don’t serve the public good.

With caution in mind, here’s a look at key parts of what will probably be known as “that Kavanaugh memo on Clinton” and the deep offense he took at a president behaving badly.

He thought Clinton was guilty as heck. Kavanaugh essentially calls Clinton a self-centered liar who used taxpayer-funded political and legal resources to carry out and help cover up an affair in the Oval Office. Kavanaugh writes:

“I have tried hard to bend over backwards and to be fair to him and to think of all reasonable defenses to his pattern of behavior. In the end I am convinced that there really are none. The idea of going easy on him at the questioning is thus abhorrent to me.”

The independent counsel should punish him to the extent possible. Kavanaugh is so offended by Clinton, he takes an unusually active approach to his and the independent counsel’s job, advocating that the limits be pushed on what they could do. Rather than merely investigate Clinton for wrongdoing, Kavanaugh argues for pressing the president in a way that could cause him to resign or to commit perjury that could lead Congress to impeach him.

Kavanaugh writes: “It may not be our job to impose sanctions on him, but it is our job to make his pattern of revolting behavior clear — piece by painful piece — on Monday.” He considered anything less an effort to “conspire” with Clinton.

“It’s basically,” Chafetz says, summarizing Kavanaugh’s thinking in this memo: " ‘Clinton is a stain on the Oval Office, and it’s our job to do everything we can to help him get him out of here.’ "

Kavanaugh thought impeachment was the best remedy in the case of a president accused of behaving badly. He writes:

“I am mindful of the need for respect for the Office of the President. But in my view, given what we know, the interests of the Office of the President would be best served by our gathering the full facts regarding the actions of this President so that the Congress can decide whether the interests of the Presidency would be best served by having a new President.”

That’s interesting, because it’s what some Trump critics advocating that Congress consider his impeachment are arguing now: that the only way to stop the damage they feel Trump has done to America is to impeach him.

Kavanaugh did not think indicting a president while in office was okay. This isn’t in this memo, but it’s in other Kavanaugh writings dating to the Clinton investigation. As The Washington Post reported earlier this month after another Kavanaugh document dump:

He expressed caution about seeking an indictment of a sitting president.

“I would send a letter to the Attorney General explaining that we believe an indictment should not be pursued while the President is in Office,” Kavanaugh wrote on Dec. 24, 1998.

The Washington Post, Aug. 10

That’s not surprising, given a decades-old Justice Department opinion that sitting presidents probably can’t be indicted, something special counsel Robert S. Mueller III seems to be aware of as he investigates Trump campaign connections to Russia.

Kavanaugh was disturbed by what he saw as attempts by Clinton to disparage an independent investigation. Of everything in the memo, this may be the single most resonant aspect today. Trump tweets daily, sometimes hourly, insulting and trying to undermine Mueller’s investigation.

Of Clinton’s actions, Kavanaugh tells Starr: “He has lied to his aides. He has lied to the American people. He has tried to disgrace you and the Office with a sustained propaganda campaign that would make Nixon blush.”

Again, we don’t know how Kavanaugh would approach any questions relating to Trump. We can’t rule out partisanship, Chafetz warned. Maybe Kavanaugh viewed Clinton so critically because Clinton was a Democrat and Kavanaugh is conservative. Another possibility is that Kavanaugh has since grown to respect the office of the presidency more than he appeared to then, or at least tempered his desire to go after a president in legal trouble.

But at least in 1998, Kavanaugh was deeply offended by a president accused of behaving badly and thought he should be impeached. You can bet Senate Democrats will ask him about that next month.