When she was 13, Clarke crossed a picket line of African-American activists protesting segregation at Woolworth's on 14th Street, believing that this was a rebellious act. However, when she came home her mother, a staunch union member, told her never to cross a picket line again, educating her about the role of direct action politics in the civil rights movement. At 16, Clarke was allowed by her parents to attend the 1963 March on Washington for Jobs and Freedom with them, despite their concerns that there might be violence. The day before the march, on the way downtown to acquire information about the route, she ran into Martin Luther King Jr., who would deliver his "I Have a Dream" speech the next day.