There wasn't one. It took people thinking outside the norm, plain and simple.

The National Woman's Party: 1) "The Nineteenth Amendment was specifically intended to extend suffrage to women. It was proposed on June 4, 1919 and ratified on August 18, 1920. The Nineteenth Amendment was the culmination of the work of many activists in favor of women's suffrage. One such group, the Silent Sentinels, protested in front of the White House for 18 months starting in 1917 to raise awareness of the issue. On January 9, 1918, President Woodrow Wilson announced his support of the amendment. The next day, the House of Representatives narrowly passed the amendment but the Senate refused to even debate it until October. When the Senate voted on the amendment in October, it failed by three votes. In response, the National Woman's Party urged citizens to vote against anti-suffrage senators up for election in the fall of 1918. After the 1918 election, most members of Congress were pro-suffrage. On May 21, 1919, the House of Representatives passed the amendment by a vote of 304 to 89, and the Senate finally followed suit on June 4, by a vote of 56 to 25. It was ratified on August 18, 1920, upon its ratification by Tennessee, the thirty-sixth state to do so. Secretary of State Bainbridge Colby certified the ratification on August 26, 1920. In Leser v. Garnett, 258 U.S. 130 (1922), the Supreme Court of the United States upheld the constitutionality of the Nineteenth Amendment." Source and further information: http://en.wikipedia.org/wiki/Nineteenth_Amendment_to_the_United_States_Constitution 2) "After the ratification of the Nineteenth amendment in 1920, the NWP turned its attention to eliminating other forms of gender discrimination, principally by advocating passage of the Equal Rights Amendment, which Paul drafted in 1923. The organization regrouped and published the magazine Equal Rights. The publication was directed mostly towards women but also intended to educate men about the benefits of women's suffrage, women's rights and other issues concerning American women. Over the next several decades, the National Women's Party authored over 600 pieces of legislation fighting for women's equality; over 300 of these were passed. In addition, the NWP continued to lobby for the passage of the Equal Rights Amendment. In 1997, the NWP ceased to be a lobbying organization. Instead, it turned its focus to education and to preserving its collection of first hand source documents from the women's suffrage movement. The NWP continues to function as an educational organization and museum." Source and further information: http://en.wikipedia.org/wiki/National_Woman's_Party