Congress passed the Nineteenth Amendment on June 4, 1919, by a narrow Senate margin of 56 to 25, after women''s suffrage supporters spent decades lecturing, writing, marching, lobbying, and practicing civil disobedience. The amendment needed ratification by 36 states to become law. Tennessee cast the decisive vote on August 18, 1920, when 24-year-old Republican state representative Harry Burn changed his vote after receiving a letter from his mother, Febb Burn, urging him to ''be a good boy'' and support ratification. Burn wore a red rose signaling opposition but had his mother''s letter in his pocket. Secretary of State Bainbridge Colby certified ratification on August 26, 1920. Between the amendment''s first introduction in Congress in 1878 and final ratification in 1920, several generations of activists pursued varying strategies to achieve what many Americans considered radical constitutional change. Ratification did not ensure full enfranchisement, as discriminatory state voting laws kept many minority women unable to vote for decades.