RACHEL MARTIN, HOST:

Choosing a Supreme Court nominee is one of the most consequential decisions a president can make. And now President Trump will get to do it a second time. Justice Anthony Kennedy made the surprise announcement about his retirement yesterday. Here's President Trump talking about it at a rally in North Dakota.

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PRESIDENT DONALD TRUMP: And I'm very honored that he chose to do it during my term in office because he felt confident in me to make the right choice and carry on his great legacy. That's why he did it.

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MARTIN: Justice Kennedy is the longest-serving current member of the Supreme Court. He earned a reputation over those many years as the swing justice, providing the deciding vote for the conservative or the liberal wing of the court in cases covering some of the most divisive issues - abortion, affirmative action, gay rights. Now President Trump has vowed to nominate a more hard-line conservative justice. So what does the future hold for some of the court's landmark decisions? We're going to ask Michael Dorf. He is a constitutional law professor at Cornell Law School, and he was a clerk for Justice Kennedy.

Thanks so much for being with us, Mr. Dorf.

MICHAEL DORF: My pleasure.

MARTIN: As someone who knows Anthony Kennedy, why do you think he decided to do this now?

DORF: You know, it's funny - if you asked that question about anybody else who was 82, people would think you were crazy.

MARTIN: (Laughter) Right.

DORF: I think justices retire mostly for the same reasons that other people do. They want to spend more time with their family in their older years. They're a bit tired. They feel that they can't do the job quite the way they want to anymore. So I think those were the predominant reasons for Justice Kennedy, as they would be for an 82-year-old who had been a partner in a law firm or a doctor or any other kind of professional.

MARTIN: Although we do live in this incredibly partisan time and we are just a few months out from a midterm election.

DORF: Yes, that's right. You know, the truth is that we're almost always in a period where an election is upcoming or there's some crucial moment. So there's really no good time to do it if you're trying to have a Supreme Court confirmation process that's going to fly under the radar.

MARTIN: Anthony Kennedy was seen as a hero and a villain at different points by both liberals and conservatives in this country. How would you define, if you could, his overarching legal philosophy?

DORF: So he was primarily a moderate libertarian is the way I would put it. That meant that he, more than anybody else on the court during his tenure - and perhaps in history, was less likely to give deference to the government, whether that meant to the federal government - and so he would strike down laws on what are conventionally called states' rights grounds or federalism grounds - but it also meant to the government in intruding into people's private lives. And so he's probably most famous for his four majority opinions in the cases upholding rights of LGBT Americans.

And he didn't see that so much as a partisan or ideological commitment so much as a reading of the Constitution's broad language protecting liberty. I can't say that I always agreed with his decisions, but I did see a kind of overarching philosophy there. It wasn't so much a jurisprudential philosophy like originalism or the living Constitution that we might have associated with other justices as it was a kind of philosophy of government.

MARTIN: Was there a decision that he made that - you say you didn't agree with him all the time - but was there one in particular that you thought flew in the face of his track record?

DORF: Well, I think this week's decision in the travel ban case - he didn't write the majority opinion in that case; he wrote a concurrence - is a little bit distressing to those of us who saw him as a champion of religious liberty and equality. Now, I understand that one might think, as the chief justice wrote and as Justice Kennedy said, that there are reasons one defers to the executive in immigration matters that one wouldn't in other contexts. But in general, Justice Kennedy was willing to look beyond such principles of deference.

So one decision of his that I think is not getting enough notice yesterday and today is his Boumediene decision for the court in 2008 in which he cast the decisive vote in favor of the rights of noncitizens to bring habeas corpus petitions, people held at Guantanamo Bay. And that was a very important ruling in terms of the scope of habeas corpus. So he doesn't always defer. That's why I thought the travel ban join was a bit of a disappointment.

You know, I'm more of a traditional liberal, I would say. So I often disagreed with him in the cases in which he was upholding states' rights. I think his Citizens United decision is generally held up by liberals like myself as destructive to American democracy. So sure, I can find lots of decisions of his that I would disagree with.

MARTIN: What does the court look like without him ideologically?

DORF: It's the Roberts court now. The median justice - the justice sort of in the middle - has been Justice Kennedy since Justice Sandra Day O'Connor's retirement in 2005. Prior to that, he and she sort of went back and forth, depending on the issue, as the median justice. But I think it's very likely that President Trump will nominate and the Senate will confirm someone to the right of John Roberts. And that means that the chief will be in the decisive seat, not just as the formal power he wields as the chief but as being able to cast the swing vote, if you will.

MARTIN: Democrats in particular have speculated that a more conservative justice will be the vote that reverses Supreme Court decisions like Roe v. Wade. You expect that to happen?

DORF: I think there's a strong possibility of that happening. Again, I think it really depends on what John Roberts wants to do. In some ways, of course, Roberts is not completely in control. It takes four justices to vote to grant review in a case. So if the four justices to his right decide they want to hear a case, then they can set the agenda.

MARTIN: Michael Dorf, constitutional law professor at Cornell.

Thanks for your time this morning.

DORF: My pleasure. Transcript provided by NPR, Copyright NPR.