In late 1918, drained by the efforts to achieve primary suffrage, Texas suffragists opted to postpone proposals for a state constitutional amendment until after World War I. They chose instead to work for ratification of the federal amendment. This was in keeping with the National American Suffrage Association's philosophy, as passage of the federal amendment was expected in January of 1919.

The Texas Equal Suffrage Association formed a Ratification Committee, chaired by Jane Y. McCallum, in anticipation of the efforts necessary to lobby the Texas Legislature for ratification once the federal amendment was passed. Minnie Fisher Cunningham moved to Washington to labor for the national office by lobbying southern Democrats in the U.S. Senate.

Prohibition arguments often overlapped with suffrage issues since most temperance leaders came to believe that woman suffrage would be the means by which to achieve their goals. Many of the Texas Equal Rights Association members were also members of the Women's Christian Temperance Union. Texas prohibitionists, needing the woman's vote, succeeded in pressing the suffragists to support an early state referendum on both prohibition and suffrage in 1919.

Although the U.S. Senate failed to pass the federal amendment in January, Hobby signed the full suffrage bill on February 5, 1919. Suffragists launched an intensive campaign, but the May 24 election mandated by the suffrage bill resulted in the amendment's defeat. Election fraud and irregular election ballots were a major cause. Another important factor was the inclusion of a citizenship clause, passage of which would have stopped the custom of permitting aliens who had filed "first papers"--an application for citizenship--to vote. In the election of May 24, "first paper" aliens were able to vote while women were not.

On June 4, 1919, the U.S. Senate passed the federal suffrage amendment. By June 28th the Texas legislature had ratified the amendment, making Texas the ninth state in the nation, and the first in the South, to do so.