In 1968, Spock signed the “Writers and Editors War Tax Protest” pledge, vowing to refuse tax payments in protest against the Vietnam War.[14] He was also arrested for his involvement in anti-war protests resulting from his signing of the anti-war manifesto "A Call to Resist Illegitimate Authority" circulated by members of the radical intellectual collective RESIST.[15] The individuals arrested during this incident came to be known as the Boston Five.[16]