On August 26, 1920, the Nineteenth Amendment to the Constitution was passed, giving American women the right to vote. The amendment had been first introduced in Congress in 1878, setting in motion supporters who demonstrated, lobbied, marched and spoke out for woman suffrage. They were often met with venomous opposition. Early on, the two main factions of the movement disagreed about how to achieve their goal, but they ultimately united in 1890 to form the National American Woman Suffrage Association and worked together to get the amendment passed. By August 18, 1920, three-fourths of the United States had agreed to the bill. Secretary of State Bainbridge Colby certified ratification of the Nineteenth Amendment on August 26.