When, exactly, did light bulbs become a conservative litmus test? Back in 2007, if you'll recall, George W. Bush signed an energy bill that tightened efficiency standards for lighting. It wasn't a big deal at the time. The bill just meant that manufacturers would slowly have to phase out their old, power-hogging incandescent bulbs in favor of something sleeker, like compact fluorescent lamps, or CFLs, starting in 2012. (This wasn't technically a ban on incandescents—more on that in a sec.) A few disgruntled libertarians complained, but life went on.

Alas, that was then. Nowadays, it's cause for bloodshed. Consider: Three Republicans are jockeying to chair the House energy and commerce committee. At a broad level, it shouldn't matter whether Fred Upton, Joe Barton, or John Shimkus chairs the committee. All three of them want to stop the EPA from curbing carbon emissions, repeal Obamacare, and prevent the FCC from regulating broadband. Which means that each of the contenders has had to dig deep for denunciations. Recently, Barton's allies have accused the front-runner, Fred Upton, of committing a grievous sin—Upton, you see, sponsored that 2007 light bulb bill. (Mind you, Barton didn't object to the bill at the time, but no matter.) The charge has spurred Glenn Beck to call Upton "all socialist" and led Rush Limbaugh to say, "No Republican complicit in nannyism, statism, can be rewarded this way." In the days since, Upton has had to backtrack and promise to "reexamine" the bulb law if he becomes chairman.

But why the uproar now? Has there been any evidence since 2007 that the new light standards are a bad idea? Not really. The case for the law is still straightforward: CFLs and other more-efficeint bulbs help reduce power-plant emissions and, over the long run, save consumers money—the EPA estimates that if every household in America swapped out one incandescent for a more efficient bulb, it'd be the same as taking 800,000 cars off the road. True, there are more economically elegant ways to reduce emissions, but Republicans are opposed to carbon taxes and the like, which means that clumsy regulations are the only things that attract political support.

Conservative think tanks like Heritage have tried to drum up a variety of objections to the bulb law, but none of them are persuasive. Yes, CFLs contain trace amounts of mercury, but it's not hard to sweep up a broken bulb safely (and the electricity savings help reduce mercury pollution from coal plants by an even greater amount). And yes, the glare from CFLs is annoying for some people. At the same time, the looming standards have spurred new advances in light-bulb technology: Some companies are developing mercury- and glare-free CFLs; others are tinkering with new hyperefficient incandescent bulbs; and still others are nudging down the cost of long-lasting LED bulbs. The market seems to be adjusting nicely, just as markets do.

The newest talking point among Republicans is that the "bulb ban" is helping to outsource jobs. Exhibit A: GE's last major incandescent factory, in Winchester, Virginia, closed down earlier this year, laying off some 200 workers—and the company was going to start importing CFLs from China. The wages of rampant nannyism? Nope. GE had been planning to trim its lighting division long before Bush ever signed the 2007 bill, because the market for incandescents had been declining for years. And GE is now adding new jobs in efficient lighting elsewhere, including 135 positions in a factory in Bucyrus, Ohio. (Fun footnote: GE actually invented the spiral-tube CFL back in 1973, in response to the oil crisis, but decided not to invest in factories—eventually the design was copied by others and China took the lead in manufacturing them.)