Answer: Roosevelt ran against his self-appointed successor, William Howard Taft, in the Election of 1912 because he believed that Taft had abandoned his progressive policies and was too beholden to big business interests. Roosevelt was frustrated by Taft's policies and believed that he was not doing enough to support the American people. In response, Roosevelt formed the Progressive Party (also known as the Bull Moose Party) and ran as their candidate in the election. He believed that this was the best way to push for progressive reforms and to bring attention to issues that he felt were being ignored.