The nomination of Judge Brett Kavanaugh to the U.S. Supreme Court is one that could, if it succeeds, reshape the court for decades, providing a deciding vote for a conservative majority on everything from abortion rights to health care, the environment and more.

But at the moment, there is an issue that overrides all of those in importance. That is the question of presidential power: How far can it go and does it — or should it — include immunity from civil and potentially criminal investigations?

Alone among all the candidates on President Donald Trump’s shortlist, Kavanaugh is on record saying presidents should be immune from civil or potentially criminal investigations while in office. In a 2009 article for the Minnesota Law Review, Kavanaugh — in an argument that surely caught Trump’s eye — wrote that Congress should exempt the president from civil lawsuits and “might consider a law exempting a President — while in office — from criminal prosecution and investigation, including from questioning by criminal prosecutors or defense counsel.”

Even the lesser burden of preparing for questioning would be time-consuming and distracting, Kavanaugh said, taking the presidential focus off the responsibilities of the office. “A President who is concerned about an ongoing criminal investigation is almost inevitably going to do a worse job as President,” he wrote.

This was not a sentiment of the moment. Despite his diligent efforts while working on the Kenneth Starr investigation of President Bill Clinton in the 1990s — he wrote the report laying out the case for impeachment — Kavanaugh said that when he began working for President George W. Bush, he began to feel differently about investigating sitting presidents. He has since expounded at length on the need to protect the presidency from civil or criminal action, including in a 2008 lecture at the University of Minnesota Law School from which he adapted his article and where he also called for Congress to enact specific protections for the presidency.

How welcome those words must have been to a man who feels the circle drawing tighter, as each indictment seems to bring special counsel Robert Mueller’s investigation closer to the Oval Office. But that is precisely why the Senate must fulfill its advise-and-consent obligations and give a thorough vetting to the thinking behind Kavanaugh’s words, particularly whether Kavanaugh believes the Constitution as written already provides some measure of immunity through separation of powers.

At 53, Kavanaugh has a résumé tailor-made for the high court. By all accounts he has a keen legal mind, is an experienced jurist and has worked in the political world at the highest levels. It must also be said that his background is a bit sheltered even for a Supreme Court justice. He is the son of a judge and a lobbyist who has lived most of his life inside the Beltway. He attended the right prep school (Georgetown), the right college (Yale) and got the right jobs. He passed muster with the conservative Federalist Society, which produced the list from which Trump drew his candidates. Kavanaugh’s elevation would be another missed opportunity to put on the land’s highest court someone whose life experience is a bit broader and more representative of the rest of the country, political leanings aside.

We would urge Republicans to resist the rush to confirmation and instead perform the due diligence that should be required of a lifetime appointment. Kavanaugh has been prolific, with more than 300 written opinions and voluminous writings throughout his career. He has expressed a strong proclivity for expanded presidential powers that should be examined at length.

And that should proceed without drawing resources from every U.S. attorney’s office in the country, as the Department of Justice has requested. The U.S. attorney field offices have important work to do and caseloads that should not be set aside for a task previously handed by the DOJ’s department lawyers. Trump was advised before selecting Kavanaugh that his lengthy paper trail might draw out confirmation proceedings. If that lengthens the proceedings, so be it.