HOW MANY Republicans does it take to change a lightbulb? Americans may soon find out. On September 4th the Trump administration announced that it was rolling back energy-efficiency standards for household bulbs. The rules, which environmental groups say would lower energy bills and reduce carbon emissions by millions of tonnes per year, were set to come into force in 2020. But the administration says they are “not economically justified” and will limit consumer choice. The Department of Energy says its action “will ensure that the choice of how to light homes and businesses is left to the American people, not the federal government.”

The controversy is reminiscent of the lightbulb wars of Barack Obama’s presidency. In 2010 Republican lawmakers became preoccupied with a set of standards, contained in a law known as the Energy Independence and Security Act, aimed at boosting the energy efficiency of American household bulbs by 25%. Although the regulations did not ban any bulbs outright, they were designed to phase out traditional incandescent bulbs in favour of more efficient compact fluorescent lights (CFLs) and light-emitting diodes (LEDs). These newer bulbs cost more up front but save consumers money over the long-term. LEDs, for example, use 75-80% less energy than incandescents, last 25 times longer and produce about ten times as much light per watt (see chart).