New U.S. Supreme Court nominee Judge Neil Gorsuch, if confirmed, would fill the vacancy left a year ago by the death of Justice Antonin Scalia, with whom he shares a similar conservative legal philosophy. His past decisions in cases involving health and energy issues indicate he believes it is up to the courts, not government agencies, to interpret laws cast with ambiguous language.

This week Pres. Donald Trump selected Gorsuch, who has been on the U.S. Court of Appeals for the 10th Circuit since 2006, from a list that appealed to conservative and evangelical voters. Gorsuch had been considered a top contender early on because of his opinion in a case about the obligations of employers to provide insurance benefits that include contraceptives.

When Gorsuch’s circuit court heard Hobby Lobby Stores v. Sebelius, he sided with the Green family, owners of the Hobby Lobby Stores, who wanted no part in providing health insurance to employees for drugs or devices that destroy fertilized eggs. Hobby Lobby argued that the Affordable Care Act’s mandate to provide such insurance violated their religious freedom. Gorsuch said the decision rested on which law should be dominant—the ACA or the another law, the Religious Freedom Restoration Act. He ruled Congress had made it clear the RFRA should override other legal mandates, if and when they encroach on religious liberty. The decision was upheld by the U.S. Supreme Court in 2014.

Gorsuch also authored a 2006 book, The Future of Assisted Suicide and Euthanasia, in which he built a legal and moral argument that intentional killing is always wrong because human life is intrinsically valuable. He does not argue against allowing a patient to refuse unwanted medical treatment and life-sustaining care, however.

Evangelical leaders were quick to praise his nomination. In a letter organized by Russell Moore, president of the Ethics & Religious Liberty Commission of the Southern Baptist Convention, signers stated “by all indication” Gorsuch would interpret the Constitution in accordance with America’s tradition of limited government and uphold the principles of protecting the unborn, strengthening religious liberty and the biblical definition of marriage and family. Gorsuch has not directly ruled on an abortion case.

Still, as a federal appellate judge, Gorsuch has issued hundreds of opinions that offer some idea of where he might stand on health and science issues. In Guitierrez-Brizuela v. Lynch, a 2016 immigration case, Gorsuch waved a red flag against the “Chevron deference”—a doctrine under which courts are supposed to defer to federal agencies on interpretations of rules that developed from a 1984 decision, Chevron v. National Resources Defense Council. “But where in all this does a court interpret the law and say what it is? When does a court independently decide what the statute means and whether it has or has not vested a legal right in a person? Where Chevron applies, that job seems to have gone extinct,” he wrote.

Ann Carlson, a professor of environmental law at the University of California, Los Angeles, says a repudiation of Chevron deference “would mark a sea change in administrative and environmental law,” where the U.S. Environmental Protection Agency and other implementing agencies often must interpret ambiguous statutory provisions, she wrote on Legal Planet, a U.C.L.A. blog. She noted legal challenges to the EPA’s Clean Power Plan are centered on such ambiguities. “The big fear many observers have if Chevron is overturned is that it would make agency rule-making even more difficult, more uncertain and more vulnerable to legal challenge. That would be bad news for environmental protection,” she wrote.

His rulings do not appear to be anti-environmental regulation, however. On renewable energy, Gorsuch has supported Colorado’s law requiring that at least 20 percent of the electricity sold by producers comes from renewable sources. The Energy and Environment Legal Institute (EELI) challenged the statute, contending that out-of-state, nonrenewable energy companies that sell on the Colorado power grid could lose business. In the 2016 case, Energy and Environmental Legal Institute v. Epel, he rejected the claim. “As far as we know, all fossil fuel producers in the area served by the grid will be hurt equally and all renewable energy producers in the area will be helped equally. If there’s any disproportionate adverse effect felt by out-of-state producers or any disproportionate advantage enjoyed by in-state producers, it hasn’t been explained to this court,” he wrote.

In 2016 Gorsuch issued an opinion that offered at least a partial shield to medical device manufacturers that had been sued over off-label uses of the devices. In Patricia Caplinger v. Medtronic he rejected the plaintiff’s claim to hold the Minnesota firm liable, pointing to federal law that bans states from imposing additional requirements on a device’s safety or effectiveness. “Allowing more regulation of medical devices could yield benefits for patient safety. But it could also mean forcing manufacturers to abide not one but 51 sets of requirements, a prospect that could deter or delay access to innovative devices and wind up hurting more patients than it helps,” he wrote.

Judge Carlos Lucero, in a partial dissent, argued against such immunity: “The notion that a device manufacturer is immune from liability for harm caused by its device when the manufacturer has pushed the device for a use that the [U.S. Food and Drug Administration] never approved is neither logical nor consistent with the Supreme Court’s prior rulings about the scope of preemption of claims arising from harm caused by medical devices.”

Gorsuch considers himself a “textualist” and “originalist” who turns to the plain text of legislation for legal intent and reads the U.S. Constitution as it was construed by the Founding Fathers. He considers Scalia a role model.

Last year he aligned himself with Scalia's judicial philosophy in a speech at Case Western Reserve University School of law."The great project of Justice Scalia's career was to remind us of the differences between judges and legislators,” he said. “Legislators may appeal to their own moral convictions and to claims about social utility to reshape the law as they think…but judges should instead strive (if humanly and so imperfectly) to apply the law as it is, focusing backward, not forward, and looking to text, structure and history to decide what a reasonable reader at the time of the events in question would have understood the law to be.”

A study by Mercer University law professor Jeremy Kidd found Gorsuch to be among the most Scalia-like of the early Trump contenders for the Supreme Court. The study found him to have a 62.2 to 79.4 percent likelihood of being the most Scalia-like of potential nominees.

Gorsuch was born in Denver but spent much of his childhood in Washington State. His mother, Anne Gorsuch, was appointed by Pres. Ronald Reagan as the first woman to head the EPA. She resigned under fire from Congress nearly two years later. During her time at the EPA she proposed deep budget cuts and favored voluntary compliance over strict regulation.

Judge Gorsuch earned a bachelor’s degree at Columbia University and a law degree from Harvard University. He then joined a private law firm in Washington, D.C., and later worked at the Department of Justice. He was also a clerk for Supreme Court justices Byron White and Anthony Kennedy.