Aprogressive reformer who was dominant force in the league of women voters during the 1920s was

The correct answer is Carrie Chapman Catt.

Catt was the founder of the League of Women Voters and the International Alliance of Women. Her advocacy for women's rights during the early 20th century was one of the biggest reasons behind the passing of the 19th amendment to the US Constitution. This amendment gave women all over America the right to vote in elections.