What role did the war on drugs play in the FBI Lennon investigation?

Question: What role did the war on drugs play in the FBI Lennon investigation?

Answer: FBI agents had been trailing John Lennon since at least December, 1971, when the ex-Beatle made his first public appearance at a US rock concert since 1966 -- a Free John Sinclair rally in Ann Arbor, MI, at which he shared the stage with several leading liberal activists, including members of the "Chicago Seven," protestors at the 1968 Democratic National Convention who were charged with conspiracy to overthrow the United States government. John Sinclair was another leading activist who had been sentenced to 10 years in prison after selling two marijuana cigarettes, or "joints," to undercover federal agents. At the rally, Lennon introduced a song he'd written specifically for the event called "John Sinclair." Two days later, Sinclair was released from prison.