During World War II, President Roosevelt instituted year-round Daylight Saving Time, called “War Time,” from February 9, 1942 to September 30, 1945. But individual states continued to turn clocks ahead one hour in spring and back one hour in fall. It was not until 1966 that Congress passed legislation setting a standard time that permanently superseded local habits.
Many personally prefer that we stick to Standard Time, since it’s supposed to be more aligned with our circadian rhythm. However, people seem to be evenly divided in their opinion about which standard we should stick with. Arizona (with the exception of the Navajo Nation) remains on Mountain Standard Time all year around.