Step 1 : Introduction to the question "Which First Lady was the first to vote for her husband in a presidential election?"
The first First Lady to vote for her husband in a presidential election was Florence Harding in 1920. Her husband, Warren G. Harding, ran as the Republican candidate in the 1920 election and became the 29th President of the United States. Florence Harding’s ability to vote for him marked a significant milestone in American history, as it occurred just after the passage of the 19th Amendment in 1920, which granted women the right to vote. Her participation in the election symbolized the beginning of a new era for women's suffrage and political involvement in the United States.