Setting the scene
Montana granted women the vote in 1914, two years before most of the nation. Pacifist suffragist and social worker Jeannette Rankin campaigned as a Republican on progressive reforms including child welfare and prohibition.
What happened
Rankin was elected to the U.S. House of Representatives in November 1916 and took her seat in 1917, becoming the first woman in Congress. She could not vote for the Nineteenth Amendment in the House because she was not seated until after some suffrage votes, though she supported it.
Why it still matters
Rankin served two nonconsecutive terms and cast the only vote against declaring war on Japan after Pearl Harbor in 1941. Memorable detail: she said 'I want to stand by my country, but I cannot vote for war'—a stance that ended her political career until she protested the Vietnam War in her eighties.
Background
She later cast a lone vote against WWII entry.