On May 19, 1969, The Supreme Court concurred with Leary in Leary v. United States, declared the Marihuana Tax Act unconstitutional and overturned his 1965 conviction. On that same day, Leary announced his candidacy for Governor of California against the Republican incumbent, Ronald Reagan. His campaign slogan was "Come together, join the party." On June 1, 1969, Leary joined John Lennon and Yoko Ono at their Montreal Bed-In, and Lennon subsequently wrote Leary a campaign song called "Come Together".

That compresses the truth a little, but...

"The thing was created in the studio. It’s gobbledygook; Come Together was an expression that Leary had come up with for his attempt at being president or whatever he wanted to be, and he asked me to write a campaign song. I tried and tried, but I couldn’t come up with one. But I came up with this, Come Together, which would’ve been no good to him – you couldn’t have a campaign song like that, right?" -- John Lennon