The Nineteenth Amendment gave women the right to vote. The text of the 19th Amendment to the Constitution reads as follows: "The right of citizens of the United States to vote shall not be denied or abridged by the United States or by any State on account of sex. Congress shall have power to enforce this article by appropriate legislation."
The proposal to add such an amendment was first introduced in Congress in 1878, but Congress did not pass the amendment till 1919 -- after the experience of women taking on greater roles in the country during the First World War. The amendment achieved ratification by a sufficient number of states and was added to the Constitution by August, 1920.
The passage of the 19th Amendment essentially doubled the number of eligible voters in the United States, since prior to its passage, only male citizens could vote.
