Time zones were first introduced in the United States in 1883 by railroad companies.^[3] In 1918, they were codified into federal law by the Standard Time Act, which also included a provision for nationwide daylight saving time modeled after European laws designed to save energy during World War I, but that component was repealed a year later due to protests by farmers.^[3] Many states subsequently introduced daylight saving time, and in 1966, the Uniform Time Act standardized the dates when it begins and ends.^[3] Hawaii, most of Arizona, and the U.S. territories have opted to observe permanent standard time,^[4] but the Uniform Time Act forbids observation of permanent daylight saving time.^[3]

The Emergency Daylight Saving Time Energy Conservation Act enacted year-round daylight saving time for a two-year experiment from January 6, 1974, to April 7, 1975, but Congress later ended the experiment early on October 27, 1974, and did not make it permanent^[5] due to unfavorable public opinion, especially regarding concerns about children walking to school and waiting for school buses on dark winter mornings.^[6][7]

In the late 2010s, resolutions were passed in more than 30 states advocating for the federal government to abolish the annual transitions.^[8]

The Sunshine Protection Act would establish a permanent daylight saving time in the U.S., leading to later sunrises and sunsets during the four months in which most of the U.S. currently observes standard time, resulting in less sunlight in the morning hours and more sunlight in the evening ones. It would not mandate that states and territories that observe permanent standard time (American Samoa, most of Arizona, Guam, Hawaii, Northern Mariana Islands, Puerto Rico, and the Virgin Islands) switch to permanent daylight saving time.^[9]

The Sunshine Protection Act was first introduced in 2018 by U.S. senator Marco Rubio (R‑FL), modeled after a 2018 Florida bill of the same name.^[10] U.S. president Donald Trump tweeted that he would be willing to sign it,^[11] but it failed to advance.^[10] A reintroduction in 2019 by Vern Buchanan (R‑FL 16th) similarly failed.^[10]

The 2021 iteration was filed in the U.S. House of Representatives by Buchanan on January 4, 2021,^[2] and in the U.S. Senate by Rubio on March 9, 2021. The bill received bipartisan support, and was cosponsored in the Senate by James Lankford (R‑OK), Roy Blunt (R‑MO), Sheldon Whitehouse (D‑RI), Ron Wyden, (D‑OR); Cindy Hyde-Smith, (R‑MS), Rick Scott (R‑FL), and Ed Markey (D‑MA).^[9] It passed the Senate by unanimous consent on March 15, 2022.^[12] Two days later, BuzzFeed News reported that many senators were not aware that a request had been made for the bill to pass via unanimous consent and were not ready to raise an objection. Rubio's office had notified every other senator's office of the request; however, it is a frequent occurrence for legislative staff to "vet the request" themselves to "decide if an issue is too benign or obviously doomed to bother their boss with." BuzzFeed identified Tom Cotton (R‑AR) as a senator who, according to a member of his staff, was vehemently opposed to the bill and would have objected to its passage had he been informed of it.^[13][14] Upon being passed by the Senate, the bill faced uncertain prospects in the House.^[15][16] Ultimately, the 117th Congress ended without the House voting on the bill.^[17]

A 2023 bill has been introduced, but is at a standstill for the time being. As of March 25, 2024^[update], the full history is as follows:

Numerous polls have found that most Americans believe that a standard time should be fixed and permanent—as many as 75% favor no longer changing clocks twice per year.^[18] One of the most common observations among researchers of varying backgrounds is that the change itself causes most of the negative effects, more so than either standard time or daylight saving time.^[1] Researchers have observed numerous ill effects of the annual transitions, including reduced worker productivity, increased heart attacks and strokes, increased medical errors,^[19] and increased traffic incidents.^[3]

The debate over the bill mainly concerns whether it is better to have more sunlight in the morning or the evening. A 2023 YouGov poll found that half of Americans supported permanent daylight time, 31% were in favor of permanent standard time, and 19% had no preference or were not sure.^[20][21] Opponents of the Sunshine Protection Act argue permanent standard time would be more beneficial to health and human welfare.^[22][23] Numerous health specialists, safety experts, and research societies consider permanent standard time better for health, safety, schools, and the economy.^{[24][25][26][27][28][29][30][31][32][excessive citations]} However the magnitude of effect in either direction is disputed.^[33] This happens partly because standard time aligns with the natural circadian cycle, whereas daylight saving time is an hour ahead. Furthermore, the majority of land within each American time zone is skewed westward, creating sunrises and sunsets that are both artifically late even without Daylight Saving Time. (There are exceptions, such as Long Island and the New England states). It is hypothesized closer harmony between standard time and biology contributes to safer morning commutes,^[24][34] improved student welfare,^[35][36] practicability of certain religious practices (such as in Orthodox Judaism and Islam),^{[37][38][39][40][excessive citations]} increased exposure to healthy morning sunlight,^[25] and higher productivity and wages.^[41] However, advocates of permanent daylight saving time argue it has its own benefits^[42] including decreased crime,^[43] less frequent traffic incidents, longer evening outdoor recreation and decreased prevalence of seasonal depression.^[44][45] Research is unclear about which time setting conserves more energy.^{[3][46][47][48][excessive citations]}

• Sunshine Protection Act at Congress.gov
• Sunshine Protection Act at GovTrack