In January 1942, just after the attack on Pearl Harbor, Congress passed a federal daylight saving law — but this time, they included a line that said the law would automatically end six months after the war did. Well, after the war ended, and DST was no longer federal law, the country descended into chaos yet again. For years. There were heated city council and school board meetings. There were furious farmers. There was at least one train crash (though, fortunately, no fatalities). There were 23 different combinations of start and end dates for DST throughout the state of Iowa in a single year. A state official in Tennessee had to be escorted to a meeting about DST by US marshals because the situation was so intense.
In 1965, St. Paul and Minneapolis couldn’t agree on when daylight saving should start; though May 23 was the official start date per Minnesota state law, St. Paul was like, “Nah, we're going to start it on May 9" and refused to back down, even after the governor was like, "Seriously, guys, please stop." So *takes deep breath* 18 of St. Paul’s suburbs were on daylight saving time; 19 were on standard time; four were on standard time BUT had town offices shift their hours so they opened/closed an hour later; one stayed on standard time but all of their businesses used daylight saving time; one observed DST ~unofficially~, and two let each individual citizen decide. And I'm not even going to try to explain how it looked across school districts and the fire and police departments. It was PREPOSTEROUS.
Elsewhere in the country, the transportation industry was at a loss for how to handle the discrepancies. Railroads operated on standard time (per federal law), but started publishing two separate timetables because they had passengers who lived in places that observed daylight saving time. Bus, train, and airline companies were forced to regularly re-print their schedules to keep up with the time changes in the cities they were passing through, something that cost the railroad industry alone $12 millions in today’s money.
In 1965, Congress realized they should probably do something about this foolishness, and it seemed like passing a federal daylight saving time law was the best option. So...there were more heated debates. Farmers got pissed. Senators and their religious fundamentalist constituents once again started talking about “God’s time.” This time around, many opponents of DST went the “THINK OF THE CHILDREN!” route, invoking images of innocent children waiting outside for the bus alone on cold, dark mornings. Representative H.R. Gross of Iowa was one of the people who used this technique, shouting, “I am not going to vote today to make myself part of a tragedy on the highways of Iowa where school children … are mowed down by a truck or car … Let the blood be on your hands, not mine!” (I can’t not read that in Alex Jones’s voice.)
TL;DR: After WWII, nobody could agree on national DST and things got Very Bad.