“I don’t know that the terms ‘climate change’ or ‘global warming’ were ever uttered in the entire year and a half of advocacy and debate around this,” Mr. Norris said.

The final vote in the South Carolina Senate was 46-0, and in the House, 103-0. You read that right.

The champion of the Energy Freedom Act, a Republican state senator named Tom Davis, explained his thinking last week, writing in an op-ed that the bill was a step toward “real competition that will provide downward pressure on the cost of producing energy.”

He is right: We are entering an era when clean electricity is going to be the cheapest electricity. That means monopolies like Duke Energy are about to get stuck with a bunch of dirty, coal-burning power plants that are becoming uneconomical.

Some utilities, it must be said, are turning into clean-energy champions. The leading one in the country is Xcel Energy, which happens to supply much of urban Colorado with power and operates in seven other states. The company has been ramping up its clean-energy commitments for years; after Mr. Polis was elected but before he took office, it committed to going 100 percent clean by 2050.

Mr. Polis, working with a legislature controlled by Democrats, wrote into law a mandatory 80 percent reduction in emissions for Xcel by 2030, along with a broader target of reducing emissions from the entire Colorado economy 90 percent by 2050. The legislative package includes a big push for electric cars, as well as measures to ensure fair treatment for workers laid off from dirty power plants.

“Colorado prides itself on being an innovative, forward-looking state,” Mr. Polis told me. “We want to lead as a state to make sure Colorado is well positioned for the renewable-energy future.”

The clean-energy picture has evolved so rapidly in the past few years that I think the situation calls for a strategic shift on the part of the Democrats. Wagging fingers in the Republicans’ faces about their climate denial has not worked. Demanding that they pass punitive fuel taxes has not worked. What seems to be working is to emphasize the local and statewide benefits of clean energy.