Hunter S. Thompson's well-known support of Senator George McGovern causes McGovern to ultimately choose him as his running mate in the 1972 Democratic National Convention - which is put off by a week or so ITTL so that it doesn't happen until after Thompson's 35th birthday passes, making him eligible for being chosen as a result. Nixon's Watergate scandal is also discovered earlier ITTL, leading to massive outcry, so Nixon ends up losing re-election to McGovern. Sadly, McGovern is assassinated by a member of the Manson Family while visiting San Francisco in 1975, so Thompson becomes the youngest president in the nation's history at age 38, and vows "instant justice" on McGovern's assassins. He picks Senator Thomas Eagleton, whose depression doesn’t get exposed during the ‘72 election ITTL, as his VP due to President McGovern formerly having an eye on him in the ‘72 election. However, despite being elected president in his own terms in '76, he loses re-election in 1980 to Ronald Reagan.
Afterwards, Thompson lays low for a few years before deciding to run for Senator of Colorado, defeating Republican incumbent William L. Armstrong in the 1984 senate election. He serves as Senator for nearly 20 years, when he decides to run again in the 2004 election for the sheer heck of it, defeating incumbent president George W. Bush in a very shocking upset, with his close friend Senator John Kerry serving as his VP (since the 22nd amendment allows presidents to be elected twice, and Thompson was only elected once back in 1976, he is eligible for re-election). However, his history of alcohol and cocaine abuse, as well as his record of depression and mental issues, eventually get exposed while he’s in office and begin to heavily rock his second term, plaguing him with many scandals as well as eventual dropping popularity. A year later than OTL, President Thompson, suffering from a particularly heavy episode of depression, decides that he has had enough of all the drama and makes an emergency TV broadcast across the entire country, announcing his resignation from office, effective immediately, and declaring that he is “signing off” for good. Nobody knows he's hiding a gun in his lap until the deed's already done. VP Kerry is eventually sworn in the next morning as the 45th president.