In 1989, Supreme Court Justice Antonin Scalia -- then a recent arrival on the bench -- delivered an emphatic endorsement of a court practice of deferring to agencies' expertise.
Speaking to Duke University School of Law that January, Scalia was 2 ½ years into what would become three decades on the court. The topic: judicial deference to agency actions. Deeply interested in administrative law, he'd taught it as a law professor before joining the court.
"Administrative law is not for sissies," he told the Duke audience.
Scalia went on to tout the so-called Chevron doctrine, holding that if Congress has been silent or ambiguous about how to tackle an issue, the courts should defer to an agency's reasonable interpretation of the law.
"Broad delegation to the executive is the hallmark of the modern administrative state; agency rulemaking powers are the rule rather than, as they once were, the exception; and as the sheer number of modern departments and agencies suggests, we are awash in agency 'expertise,'" he said.
"In the long run, Chevron will endure and be given its full scope," he added, because "it more accurately reflects the reality of government, and thus more adequately serves its needs."
The Chevron doctrine, which sprang from an environmental case decided before Scalia joined the court, is central to environmental law, where cases frequently center on whether agency regulations can be deemed reasonable interpretations of the law.
The doctrine has also been the topic of vigorous debate in legal circles lately. In light of some high-profile opinions -- including the Supreme Court ruling upholding the Obama administration's health care law -- scholars and experts have suggested that the court's conservative wing is looking to chip away at that doctrine, and that the leeway long given to agencies could be in jeopardy.
Environmental advocates have been troubled by several of the court's recent opinions. In the health care case, Chief Justice John Roberts wrote in the majority opinion for the court that Chevron didn't apply because the health care case was "extraordinary" and centered on a question of "deep 'economic and political significance.'"
For some, that opinion forecast trouble for major environmental rules like the Obama administration's Clean Power Plan, which also has major economic and political significance.
Others remained confident Chevron would remain intact, including the Obama administration's top environmental lawyer.
In a speech last November, the head of the Justice Department's Environment and Natural Resources Division, John Cruden, pointed to Scalia's Duke remarks as he argued that "Chevron is not -- in environmental terms -- a dead or endangered species" (Greenwire, Nov. 11, 2015).
So will the absence of Scalia, who died last weekend, mean the court has lost a strong champion of deferring to environmental agencies?
Many legal experts say no.
Scalia "as much as any other judge actually made Chevron what it is today," said Lisa Heinzerling, a law professor at Georgetown University and a former top official in the Obama administration U.S. EPA. But "his views on Chevron, I think, became very complicated in recent years."
In at least two recent cases regarding major Obama administration air pollution rules, she said, "he wrote majority opinions which did not give agencies deference and did not give EPA deference, and seemed to, in my opinion, create a whole different set of rules."
Those cases are the Supreme Court's decisions in cases that scaled back major EPA rules for industrial emissions of greenhouse gases and for power plants' toxic air pollution.
In the greenhouse gas case, Scalia wrote for the majority, finding that EPA had unlawfully interpreted the Clean Air Act when it revised the greenhouse gas emission thresholds that trigger permitting rules for facilities like factories and power plants.
Scalia also wrote the court's 5-4 2015 opinion striking down the administration's rule to limit mercury from power plants, finding that the agency hadn't properly considered costs.
"In both cases, Justice Scalia came out strongly in favor of an overarching interpretive principle that would reject agency interpretations that went against that principle," Heinzerling said. "It's really important," she added, noting that those were the cases cited when challengers of the agency's landmark Clean Power Plan asked the high court to block the rule. The court agreed to halt that climate rule just days before Scalia's death.
"There's every reason to believe that those cases were central to the grant of that stay," Heinzerling added.
By contrast, Case Western Reserve University School of Law professor Jonathan Adler said he doesn't think either of those cases reflected "any backing away from Chevron" by Scalia. He and others pointed to a 2013 telecommunications case opinion written by Scalia, City of Arlington, Texas, v. Federal Communications Commission, as recent evidence that Chevron was alive and well in the high court.
That opinion "was a fairly full-throated defense of a robust Chevron doctrine," Adler said. He noted that Scalia had expressed "grave doubts" about another type of agency deference regarding "the extent to which there should be deference to agency interpretations of their own regulations -- and I think he indicated that he was ready to curtail or eliminate such deference if the proper case arose."
Others are more skeptical about Scalia's adherence to Chevron.
"Justice Scalia recited adherence to Chevron, but in fact he showed remarkably little deference for EPA in particular," said Michael Gerrard, a law professor at Columbia University and director of the Sabin Center for Climate Change Law.
In the environmental domain, "it seems that in the last few years that the court has been more skeptical of enlargement of agency authority," said Michael Wara, a law professor at Stanford University. "We'll have to see where that goes with a new justice."
If a Democrat appoints the next nominee, he expects "you're going to see a greater willingness to allow agencies to promulgate regulations that are new and maybe regulate new areas."
Click here to read Scalia's 1989 speech.