Four countries tried it

Congress killed its own experiment in ten months

In the middle of the oil embargo, Congress passed the Emergency Daylight Saving Time Energy Conservation Act. Nixon signed it on 15 December 1973. It put the country on year-round daylight time for a two-year trial beginning 6 January 1974, on the stated finding that this "would produce an energy saving in electrical power consumption."

On 5 October 1974, Ford signed the amendment that restored standard time for the winter. The trial had run for under ten months of its two years.

That fact needs no interpretation and no casualty figures, which is precisely why we lead with it. Congress authorised two years of exactly what H.R. 139 proposes and pulled the plug before the first winter was out.

Britain, Portugal, Russia

• UK 1968–71The British Standard Time Act held clocks at GMT+1 year-round from October 1968. After three winters and a free vote in the Commons on 2 December 1970, Britain went back to GMT in October 1971. The road-safety data was genuinely favourable and remains argued about, because the breathalyser arrived the year before and was suppressing evening casualties at the same time.
• Portugal 1992–96Portugal moved to Central European Time in 1992 for EU alignment and hoped-for energy savings. Winter sunrises in the north reached 9am, parents' associations protested about children walking to school in the dark, the savings did not appear, and the government reversed it in 1996.
• Russia 2011–14The most instructive one. Medvedev put Russia on permanent summer time in 2011. Moscow's sunrise reached 10:00am at the start of January. After three winters the Duma reversed it near-unanimously, and on 26 October 2014 Russia moved not back to switching but to permanent standard time, where it has stayed.

Mexico is the recent data point on the other end. It abolished daylight saving time entirely in October 2022 on explicit health grounds, keeping only its US border municipalities on the American schedule.

Turkey, Jordan and Syria adopted permanent daylight time and kept it, so the pattern is not universal. But every high-latitude country that tried it reversed, and the reason was always the same: dark winter mornings, told through schoolchildren.

The things everybody knows that are not true

Franklin did not invent it. His 1784 letter to the Journal de Paris is satire. He proposed waking Parisians with church bells and cannon fire, taxing shuttered windows and rationing candles. He proposed no clock change of any kind, and could not have — standardised time zones were a century away.

Farmers did not ask for it. They were its most effective opponents. Cows and dew do not read clocks, and shifting the clock misaligned farmers with the town buyers and rail schedules they sold into. The farm bloc drove the 1919 repeal through over two Wilson vetoes, overriding 223–101 in the House and 57–19 in the Senate within a year of the Armistice. Daylight time's actual constituency was urban retail and recreation, and it still is.