Passed by Congress June 4, 1919, and ratified on August 18, 1920, the 19th amendment guarantees all American women the right to vote. Achieving this milestone required a lengthy and difficult struggle; victory took decades of agitation and protest. Beginning in the mid-19th century, several generations of woman suffrage supporters lectured, wrote, marched, lobbied, and practiced civil disobedience to achieve what many Americans considered a radical change of the Constitution. Few early supporters lived to see final victory in 1920.