President Woodrow Wilson formally introduced the United States to daylight saving time in 1918, justifying it as wartime thrift. Over the following century it was variously resisted, overturned, reintroduced and modified, reaching its current dimensions with the Energy Policy Act of 2005. Amid all that effort, nobody has been able to demonstrate conclusively that adjusting clock time to the waxing and waning of daylight hours saves energy as intended. (In fact, the opposite seems to be true.) More at The Washington Post.