But among the Republican donor crowd, Pruitt distinguished himself as attorney general of Oklahoma. In that role he sued the EPA at least 14 times on states’ rights grounds seeking to block the Obama administration’s climate-change plan, its protections against airborne mercury, its airborne-smog rule, and several more. His own website brags that he is “a leading advocate against the EPA’s activist agenda.”

Now he will be the one setting the agenda. Wednesday’s questioning unfolded as partisan ping-pong, with Republicans and Democrats trading off the dais. It fell into a pattern. Republicans would complain about an EPA rule that their constituents found particularly burdensome and ask Pruitt to alter it. (Their most common target: The “Waters of the United States” rule, which broadly defines what constitutes a federal waterway under the Clean Water Act.) Pruitt would demur, replying that he could only do what the federal statutes allowed him—and then nonetheless assure the senator that his or her reading of the same statute seemed, to him, to be entirely sensible.

Then a Democrat would take the stand. Inevitably they would ask about climate change. In his opening statement, Pruitt outlined his talking points on the issue: “Science tells us that the climate is changing and human activity in some manner impacts that change,” he said. “The human ability to measure with precision the extent of that impact is subject to continuing debate and dialogue, as well they should be.” This just isn’t right: The international scientific consensus, hard-won after many decades, is that human activity is the dominant cause of modern-day global warming.

One Democratic senator after another attempted to weaken Pruitt’s resolve on global warming. They would recount its many consequences and the seriousness of the science. “Ten years ago we were talking about models. We don’t need models now, because we have facts on the ground,” said Jeff Merkley of Oregon. Merkley talked about how oysters were struggling off his state’s coast because of ocean acidification. Its moose were dying because of a thriving tick population, he said. Sheldon Whitehouse of Rhode Island added that climate change was killing his state’s fisheries.

Pruitt sat and listened and smiled. He said he granted that—thanks to a landmark 2007 Supreme Court case and a 2009 endangerment finding—the EPA had an “obligation” to regulate carbon dioxide. But he did not say what that obligation entailed, nor did any Democratic senator ask him to go into specifics.

Only Senator Bernie Sanders succeeded in agitating the nominee. Sanders pressed Pruitt on the science, pointing out that researchers agree that human activity is the driving cause of climate change. When Pruitt pointed again to the statutes, Sanders asked him for his personal views on global warming.