Final answer:
Women in America earned the right to vote in national elections in 1920, when the 19th Amendment was ratified after a concentrated suffrage movement and significant female contributions during World War I.
Step-by-step explanation:
Women in America obtained the right to vote in national elections in 1920 thanks to the ratification of the 19th Amendment. This historical milestone was the result of decades of arduous campaigning by suffragettes and marked a significant turn in American democracy and gender equality. Following passage by Congress in 1919, the amendment needed the ratification of three-fourths of the states; this was achieved when Tennessee became the thirty-sixth state to ratify it in August 1920. Women like Carrie Chapman Catt and Alice Paul were among those who cast their ballots for the first time in the presidential election of November 1920.
Leading up to this pivotal moment, various states had been gradually extending voting rights to women, with states like Wyoming, Utah, Idaho, and Colorado granting these rights by 1900. The efforts of suffragettes included lobbying, public parades, and education campaigns, convincing male voters to support their cause. The successful campaigns were also influenced by the role of women during World War I where their contributions, including extensive work in war industries, led many politicians to recognize their potential as voters.