Neil Gorsuch, President Trump’s pick for the U.S. Supreme Court, is deeply interested in matters of life and death. His most lasting legacy from his time on the Tenth Circuit Court of Appeals is likely Hobby Lobby vs. Sebelius, a case about religious objections to the rules on birth-control coverage in the Affordable Care Act, which later became a landmark Supreme Court decision. But he hasn’t confined his writing to briefs and rulings. In 2006—the year he joined the Tenth Circuit—he published a book called The Future of Assisted Suicide and Euthanasia, outlining the moral, legal, and logistical challenges that emerge at the end of life.

The most remarkable thing about the book is its measuredness. Gorsuch is a Jesuit-educated Episcopalian, but he does not rely on theology to make his argument. In fact, he takes pains to ground his work in “secular moral theory,” laying out a careful case based on the writings of thinkers from Aquinas and Epicurus to contemporary scholars Peter Singer and Ronald Dworkin. His work reads more like a philosophy paper than a legal brief, which is appropriate given his background: He holds a doctorate in philosophy from Oxford.

Gorsuch reveals a few interesting lines of thinking in his book. First, it’s clear that he’s deeply interested in fundamental moral principles. The common wisdom around his nomination is that he’s an originalist, reading laws and the Constitution based on their authors’ intended meaning. During his nomination announcement, he emphasized this principle: “I respect … the fact that in our legal order it is for Congress and not the courts to write new laws,” Gorsuch said. “It is the role of judges to apply, not alter, the work of the people’s representatives.”

And yet, after laying out a short history of suicide, Gorsuch argues that “all human beings are intrinsically valuable and the intentional taking of human life by private persons is always wrong.” The act of summoning death—whether by administering lethal drugs or pulling the plug on a life-support machine—is murky, but the intention matters, he says. “Once we open the door to excusing or justifying the intentional taking of life as ‘necessary,’” he writes, “we introduce the real possibility that the lives of some persons (very possibly the weakest and most vulnerable among us) may be deemed less ‘valuable,’ and receive less protection from the law, than others.”

He’s also attentive to the potential for abuse accompanying the “right” to end one’s life. While assisted suicide may reduce people’s pain—as has been argued by many utilitarian thinkers, including Gorsuch’s fellow  judge Richard Posner—this isn’t enough reason to legalize assisted suicide, Gorsuch says. In practice, few governments require doctors to provide proof of intolerable pain before facilitating life-ending procedures, he argues. Instead, “the impulse for assistance in suicide, like the impulse for old-fashioned suicide, might more often than not be the result of an often readily treatable condition,” such as depression, he suggests.

The section that may be most interesting to political activists is his discussion of abortion. He writes at length on Planned Parenthood v. Casey, the 1992 case authored in part by Anthony Kennedy, one of the two Supreme Court justices for whom Gorsuch clerked. As Gorsuch notes, “the plurality in Casey expressly sought to provide a firmer basis for the abortion right and to shore up the reasoning behind Roe’s result.” Because Casey dealt with the beginning of life, Gorsuch reasons, it also has implications for the end of life.

The justices used two arguments in Casey, Gorsuch writes: They sought to provide a “reasoned judgment” on abortion restrictions; and they argued that “respect for long-settled law required continued adherence to Roe’s basic teachings.” This decision is known as one of Kennedy’s signatures, since he was a key swing voter in the case. It has also provided the basis for recent defenses of abortion rights, including this summer’s Supreme Court case, Whole Woman’s Health v. Hellerstedt.

Gorsuch dismisses the “reasoned judgement” on abortion out of hand. The Casey decision contains a section which the late Justice Antonin Scalia derided as the “famed sweet-mystery-of-life passage”:

At the heart of liberty is the right to define one’s own concept of existence, of meaning, of the universe, and of the mystery of human life. Beliefs about these matters could not define the attributes of personhood were they formed under the compulsion of the State.

Gorsuch does not find this compelling. It’s “unclear whether Casey’s ‘mystery of life’ passage is properly understood as a persuasive but non-binding dictum or an exception-less holding,” he writes. He argues that a number of activities—including polygamy, dueling, prostitution, and drug use—would have to be allowable if this “right to define one’s own concept of existence” really exists. He thinks Casey is much more compelling as a decision based on settled legal precedents than the groundwork for new legal rights, including the right to die.

But neither does he come out as a clear abortion opponent. He gives some deference to Justice Sandra Day O’Connor’s opinion that abortion is a “unique” issue, noting that the Court found in Roe that a fetus does not have the rights of a “person” for the purposes of the Fourteenth Amendment. This is why he’s so fascinated by the question of assisted suicide. According to the Supreme Court, “only one person’s autonomy interest at risk in the abortion context: the woman’s,” he writes. But in places where assisted suicide is legal, he writes, two different kinds of autonomy are at stake: that of people who want to control their death, and that of people “whose lives may be taken without their consent due to mistake, abuse, or pressure.” While Trump promised on the campaign trail to appoint pro-life justices to the Supreme Court, and pro-life groups have praised Gorsuch’s nomination, Matt Ford reports that he has never written a major decision on abortion. His book doesn’t suggest a clear position one way or the other.

Assisted suicide might seem like an odd area of focus for a rising legal star. But if Gorsuch is confirmed, it’s as likely as not that he’ll hear a case on the subject during his time on the Court. Colorado voters just approved a ballot measure on assisted suicide in November, and California’s law allowing the procedure took effect just months before that. D.C. is currently wrestling with Congress over its “death with dignity measure,” which was recently approved by the city council and then signed by Mayor Muriel Bowser in December. Other states, including Oregon, Vermont, and Washington, already allow assisted suicide, and a 2009 Montana Supreme Court decision set a precedent for the procedure in that state.

As Gorsuch noted in his book, end-of-life issues are an unclear and confusing area of law. If cases on assisted suicide make their way to the high court, at least one justice will have staked out his position. On other issues of life and death—including abortion and contraception—it’s less certain where Gorsuch might stand, although his past offers some clues. In that way, he’s much like his former boss, Kennedy: a jurist focused on life’s existential questions, but whose vote is ultimately unclear.