Now, of course, everything is in flux. In the worst case, with a sufficiently pliant Congress, Mr. Trump could roll back a decade of progress on climate change. Barring some miraculous conversion on Mr. Trump’s part, his election cannot be interpreted as anything but bad news for the climate agenda.Yet despair might be an overreaction.For starters, when Mr. Trump gets to the White House, he will find that the federal government actually has relatively little control over American energy policy, and particularly over electricity generation. The coal industry has been ravaged in part by cheap natural gas, which is abundant because of technological changes in the way it is produced, and there is no lever in the Oval Office that Mr. Trump can pull to reverse that.The intrinsically weak federal role was a source of frustration for Mr. Obama and his aides, but now it will work to the benefit of environmental advocates. They have already persuaded more than half the states to adopt mandates on renewable energy. Efforts to roll those back have largely failed, with the latest development coming only last week, when Gov. John Kasich of Ohio, a Republican, vetoed a rollback bill.