London joined the Socialist Labor Party in April 1896. In the same year, the "San Francisco Chronicle" published a story about the twenty-year-old London's giving nightly speeches in Oakland's City Hall Park, an activity he was arrested for a year later. In 1901, he left the Socialist Labor Party and joined the new Socialist Party of America. He ran unsuccessfully as the high-profile Socialist candidate for mayor of Oakland in 1901 (receiving 245 votes) and 1905 (improving to 981 votes), toured the country lecturing on socialism in 1906, and published two collections of essays about socialism: "War of the Classes" (1905) and "Revolution, and other Essays" (1906).