President Donald Trump has chosen his nominee for Anthony Kennedy’s seat on the Supreme Court: DC Circuit Court of Appeals judge Brett Kavanaugh.

Kavanaugh, 53, is a candidate straight out of Supreme Court central casting: He went to Yale and Yale Law (every current justice either attended that school or Harvard Law); he clerked for two federal appellate judges, including the well-known Alex Kozinski; worked in the solicitor general’s office in the George H.W. Bush administration; and then clerked for Anthony Kennedy on the Supreme Court. Since 2006, he has sat on the DC Circuit, which also produced current justices John Roberts, Clarence Thomas, and Ruth Bader Ginsburg.

It’s not for nothing that on Sunday the Federalist Society’s Leonard Leo, who has been Trump’s most important adviser on court nominations, singled Kavanaugh out as one of the two most promising contenders for Kennedy’s seat, alongside the Seventh Circuit’s Amy Coney Barrett.

His resumé is the one every ambitious college Republican hoping to be on the Supreme Court one day dreams of building. Sen. Dick Durbin (D-IL) once called him the “Forrest Gump of Republican politics.” But his likely nomination is sparking substantial debate among movement conservatives. He has his defenders, but concern has been growing in right-wing legal circles about his decisions in religious liberty cases and on Obamacare. Even cautiously pro-Kavanaugh writers are skeptical he’s the best possible pick. “There’s a difference between a home run and a grand slam,” as National Review’s David French put it.

Senate Majority Leader Mitch McConnell has expressed concern that Kavanaugh’s long track record will produce too many documents for the Senate to pore over, elongating the confirmation process and making it hard to get Kavanaugh on the court quickly. Trump himself reportedly resents Kavanaugh’s closeness to the Bush family.

That said, Kavanaugh would almost certainly fall to the right of Anthony Kennedy as a Supreme Court justice, and enable a rightward shift in the Court’s jurisprudence for years or decades to come. Even more concerning for liberals, he has suggested enhancing the president’s power to block criminal and civil actions against him, a potentially worrisome position when the president nominating him is under investigation and facing multiple lawsuits.

Kavanaugh’s career before the Supreme Court

Born and raised in suburban Maryland, the son of two lawyers (his mother a trial judge), Kavanaugh was educated at the tony all-boys Catholic high school Georgetown Prep, where he was two years ahead of Supreme Court Justice Neil Gorsuch.

Kavanaugh’s first legal writings came in a 1989 note for the Yale Law Review, where he also served as notes editor. The piece concerned the 1986 Supreme Court case Batson v. Kentucky, a landmark ruling that barred prosecutors from excluding jurors from cases based solely on their race.

In between his appellate clerkships and his time with Kennedy, Kavanaugh worked in the solicitor general’s office under George H.W. Bush. The solicitor general (SG) is a Justice Department official who represents the federal government before the Supreme Court; the office offers some of the most interesting and high-stakes legal work in Washington, and junior attorney positions there are highly coveted. The SG under George W. Bush was Kenneth Starr, who took a shine to Kavanaugh and hired him to join the independent counsel’s office in 1994.

Once on Starr’s team, Kavanaugh was tasked with investigating the death of deputy White House counsel Vince Foster in 1994, which many conservatives believed (absurdly) to be suspicious — a murder rather than a suicide. Kavanaugh and the rest of Starr’s investigators concluded that it was indeed a suicide.

The year following his report’s release, Kavanaugh argued the only Supreme Court case of his career, claiming that he could compel Foster’s lawyer to turn over notes on their conversation shortly before Foster’s death. (The Court rejected that argument, 6-3, with conservative Chief Justice William Rehnquist writing that attorney-client privilege precluded the notes’ release, and Kavanaugh’s former boss Kennedy joining the majority.)

Eventually, Kavanaugh, and the rest of Starr’s team, moved on from the substance of the Whitewater real estate deal to the matter of Clinton’s affair with Monica Lewinsky. In his history of the investigation, The Death of American Virtue: Clinton vs. Starr, Duquesne University’s Ken Gormley notes that Kavanaugh, “considered one of Starr’s intellectual heavy-lifters, pushed hardest to confront Clinton with some of the dirtiest facts linked to his sexual indiscretions with Lewinsky.” Gormley continues:

In a memo to “Judge Starr” (with a copy to “All Attorneys”), dated just two days before the grand jury showdown, Kavanaugh disclosed a stark division within [the Office of the Independent Counsel] over how to handle this slippery president. He wrote: After reflecting this evening, I am strongly opposed to giving the President any “break” … unless before his questioning on Monday, he either i) resigns or ii) confesses perjury and issues a public apology to you. I have tried hard to bend over backwards and to be fair to him.… In the end, I am convinced that there really are [no reasonable defenses]. The idea of going easy on him at the questioning is thus abhorrent to me… [T]he President has disgraced his Office, the legal system, and the American people by having sex with a 22-year-old intern and turning her life into a shambles — callous and disgusting behavior that has somehow gotten lost in the shuffle. He has committed perjury (at least) in the [Paula] Jones case. … He has tried to disgrace [Ken Starr] and this Office with a sustained propaganda campaign that would make Nixon blush. Kavanaugh listed ten sample questions, however explicit and unsavory, that he believed Starr and his questioners should ask. They included the following: …If Monica Lewinsky says that you ejaculated into her mouth on two occasions in the Oval Office area, would she be lying? If Monica Lewinsky says that on several occasions you had her give [you] oral sex, made her stop, and then ejaculated into the sink in the bathroom off the Oval Office, would she be lying? If Monica Lewinsky says that you masturbated into a trashcan in your secretary’s office, would she [be] lying?

Starr’s team didn’t ask those precise questions, but did ask similar ones (such as “If Monica Lewinsky says that you used a cigar as a sexual aid with her in the Oval Office area, would she be lying?”). Gormley writes that after Clinton’s testimony, “Brett Kavanaugh patted [Solomon] Wisenberg” — one of the Starr attorneys who questioned the president — “on the back and quietly congratulated him for asking the ‘sex questions.’” (That said, according to Bob Woodward’s book Shadow, Kavanaugh objected to the prurient tone of the Starr report, arguing that the level of sexual detail was not needed.)

After working with Starr, Kavanaugh continued to compile a legal record that would lead to Durbin’s description of him as “the Zelig or Forrest Gump of Republican politics. You show up at every scene of the crime … whether it is Elián González or the Starr Report, you are there.”

And indeed, Kavanaugh would represent the 6-year-old González pro bono in an attempt to keep him from being deported to Cuba in 2000. (González was eventually returned to his father in Cuba, where he still lives today.) Kavanaugh also worked on Bush’s legal team during the 2000 Florida recount, which resulted in Bush winning a party-line Supreme Court vote to install him in office.

Once Bush was president, Kavanaugh worked in his White House counsel’s office from 2001 to 2003, and then from 2003 to 2006 as his staff secretary, the person charged with providing briefing materials and other documents to the president. In 2003, Bush appointed Kavanaugh to his post on the DC Circuit, but he languished in the Senate until 2006, in the aftermath of the Gang of 14 deal, to clear Bush appellate court appointments.

In an excellent profile of Kavanaugh for Ozy, Daniel Malloy explains that Kavanaugh’s history of partisan legal service delayed his confirmation:

Given Kavanaugh’s GOP track record and lack of judicial experience, Sen. Chuck Schumer, D-N.Y., called the nomination “not just a drop of salt in the partisan wounds; it is the whole shaker.” Kavanaugh, calm and poised during his hearings, dodged questions about White House debates on judges and torture. He said he would follow Supreme Court precedent on abortion rights but wouldn’t give a personal view on the Roe v. Wade decision.

While he waited for his own confirmation, Kavanaugh advised the president on replacing retiring Associate Justice Sandra Day O’Connor and deceased Chief Justice William Rehnquist in 2005. In his memoir Decision Points, Bush credits Kavanaugh with helping him decide to nominate John Roberts to replace Rehnquist: “Brett told me that [appellate judge J. Michael] Luttig, [Samuel] Alito, and Roberts would all be solid justices. The tiebreaker question, he suggested, was which man would be the most effective leader on the Court — the most capable of convincing his colleagues through persuasion and strategic thinking. I believed Roberts would be a natural leader.”

Why (some) conservatives are worried about the conservative Kavanaugh

With a record like his, Kavanaugh has understandably drawn fire from liberals. But some of his loudest critics today come from the right.

With 12 years on the bench, Kavanaugh has had plenty of time to accumulate a controversial record of decisions, and indeed his time on the DC Circuit provides ammunition for some of his harshest critics — on the conservative side.

Of particular note is his dissent in the case of Seven-Sky v. Holder, a constitutional challenge to the Affordable Care Act decided by the DC Circuit in 2011. By a 2-1 margin, the DC Circuit upheld the law as legitimate under the Commerce Clause (which empowers Congress to regulate interstate commerce), but Kavanaugh dissented, not because he thought the law was unconstitutional but because he thought the court lacked jurisdiction to consider the question, under 1867’s Anti-Injunction Act. That law bars people from challenging taxes until after they’ve paid them, and because Kavanaugh viewed the individual mandate as a tax, he thought it could not be challenged until the first mandate penalties were levied in the spring of 2015.

This, naturally, infuriates conservatives considering his nomination today, because the argument that the mandate is a tax ultimately enabled John Roberts to rule it constitutional and save most of the law in 2012. Roberts denied that the Anti-Injunction Act applied, but accepted the tax argument for considering the mandate’s constitutionality.

“In Kavanaugh’s view, the mandate could fit ‘comfortably’ within Congress’ constitutional powers,” Christopher Jacobs, a prominent critic of Obamacare, writes in The Federalist. “Even as he ‘do[es] not take a position here on whether the statute as currently written is justifiable,’ Kavanaugh concludes that ‘the only potential Taxing Clause shortcoming in the current individual mandate provision appears to be relatively slight.’”

Worse still from Jacobs’s perspective, Kavanaugh even suggested language tweaks Congress could adopt that he thought would shore up the law’s constitutionality. “Conservatives might argue amongst themselves about which is worse: An unelected judge opining on how a mandate to purchase a product could meet constitutional muster, or that same unelected judge giving Congress instructions on how to ensure it will,” Jacobs concludes.

One of Kavanaugh’s former clerks, University of Louisville law professor Justin Walker, responded to Jacobs by noting that Kavanaugh also used his dissent to call the individual mandate “a law that is unprecedented on the federal level in American history,” and said a decision upholding it would be “a jarring prospect” that would “usher in a significant expansion of congressional authority with no obvious principled limit.” Walker, who clerked for Kennedy in 2011-2012, argues that Kavanaugh’s dissent was used as a roadmap for Supreme Court conservatives dissenting and arguing the law was unconstitutional, rather than as a roadmap for Roberts.

Kavanaugh’s record on religious liberty has also sparked conservative ire. A curiously anonymous writer at the Federalist highlights three cases in particular:

1) Newdow v. Roberts, which reached the DC Circuit in 2010, in which atheist activist Michael Newdow challenged the “so help me God” provision of the presidential oath. Kavanaugh agreed with the two other conservatives on his panel that the challenge failed, but concluded that the plaintiffs at least had standing to bring the case as “offended observers.”

“The fact that Kavanaugh was willing to expand standing in the area of the Establishment Clause beyond that which the Supreme Court has expressly done in the past is bad news for religious liberty,” the anonymous Federalist author writes. “If his views were adopted by other courts, then other frivolous claims attacking religion in the public square would have a better chance of being heard in federal courts.”

2) In 2015, Kavanaugh dissented from the DC Circuit’s refusal to reconsider a religious liberty challenge to Obamacare’s contraceptive mandate en banc, or as a full court rather than a panel. He writes that he would rule in favor of the challenge, that the mandate unconstitutionally burdens religious freedom.

But that’s not enough for the anonymous Federalist author or National Review’s David French, who note that Kavanaugh interpreted the Supreme Court’s Hobby Lobby ruling as saying that the government has “a compelling interest in facilitating women’s access to contraception.” They both found this to be an erroneous, unacceptable conclusion.

3) In 2008, Kavanaugh joined a majority opinion in Kaemmerling v. Lappin, ruling against a prisoner who claimed that a federal law requiring him to provide a DNA sample violated his free exercise of religion. While the Federalist author claims the decision’s conclusion was correct, she finds that the reasoning in the decision was too broad and enabled too large an encroachment on religious liberty in the future.

The anonymous author concludes, “All of this isn’t to say Kavanaugh would be an unmitigated disaster for religious freedom on the Supreme Court. He does sometimes vote for a pro-religious liberty outcome. … This is cold comfort for the millions of Americans for whom religious liberty is not only the defining freedom of their existence, but also the one they feel is most under threat.”

In the same publication, executive editor Joy Pullmann writes that Trump would lose her vote if he picked Kavanaugh because it would break “his promise to appoint judges who will not force Americans to spurn God to participate in the public square.”

Other conservatives, like Ed Whelan at National Review, have furiously pushed back on Kavanaugh’s critics, arguing they misunderstand decisions where his hands were tied by Supreme Court precedent, or whose reasoning is not as problematic as his conservative detractors claim.

Why liberals fear Kavanaugh on the Court

Liberals, naturally, will find much more of concern in Kavanaugh’s record. There is, for one thing, his suggestion in the Obamacare case Seven-Sky v. Holder that a future president could choose to nullify Obamacare by just not enforcing it, writing, “Under the Constitution, the President may decline to enforce a statute that regulates private individuals when the President deems the statute unconstitutional, even if a court has held or would hold the statute constitutional.”

Kavanaugh has also ruled in favor of the National Security Agency’s expansive call record surveillance operation, arguing that collecting these records did not constitute a “search,” and that even if it did, the government can take such records if it has a “special need” to prevent terrorism, even if this burdens the constitutional rights of those searched. That’s a truly expansive rationale that makes even many conservatives uneasy. He also worked to limit challenges to detention for terror suspects, and recently wrote that he thinks the Consumer Financial Protection Bureau is unconstitutional on separation of powers grounds.

His views on executive power may continue to worry liberals as the Robert Mueller investigation unfolds. In a 1998 Georgetown Law Journal article titled, “The President and the Independent Counsel,” written shortly after his service to Starr, Kavanaugh wrote that the independent counsel should be appointed by the president and approved by Congress, not by a panel of judges, to shore up the position’s constitutionality. This would have somewhat weakened the position’s independence relative to the executive; the independent counsel statute has since lapsed and the position no longer exists.

Further, he wrote that, “Congress should establish that the President can be indicted only after he leaves office voluntarily or is impeached by the House of Representatives and convicted and removed by the Senate” and that Congress should bar the President from claiming executive privilege and refusing to divulge information in criminal cases, except as a matter of national security.

“The proposals would enhance the public credibility of special counsel investigations, reduce the inherent tension between the President and the special counsel, and better enable a special counsel to conduct a thorough and effective law enforcement investigation of executive branch wrongdoing,” Kavanaugh concluded.

In 2009, he went further and argued that the president should be exempted from both criminal prosecution and civil suits while in office, arguing that the latter should be delayed until he leaves the presidency:

A … possible concern is that the country needs a check against a bad-behaving or law-breaking President. But the Constitution already provides that check. If the President does something dastardly, the impeachment process is available. No single prosecutor, judge, or jury should be able to accomplish what the Constitution assigns to the Congress. … The President’s job is difficult enough as is. And the country loses when the President’s focus is distracted by the burdens of civil litigation or criminal investigation and possible prosecution.

With Kavanaugh’s nomination, expect Democrats during the confirmation hearings to focus heavily on his apparent view that no one but Congress should be able to hold Donald Trump criminally accountable as long as he remains in office.