Both Theodore Roosevelt and William Howard Taft made significant contributions to the progressive reform movement in the United States. Roosevelt, who served as President from 1901 to 1909, is often credited with leading the charge for progressive reform. He was a strong advocate for regulating big business, protecting the environment, and promoting social justice. Roosevelt's "Square Deal" policies aimed to provide a fair balance between the interests of business, labor, and the general public. He also established a number of conservation measures, including the creation of national parks and forests, and worked to improve working conditions for laborers.
Taft, who served as President from 1909 to 1913, also supported progressive reform, though perhaps not to the same extent as Roosevelt. He continued many of Roosevelt's policies, including regulation of big business and conservation efforts, and also implemented his own progressive reforms, such as the creation of the U.S. Children's Bureau to address child labor and welfare issues.
Overall, Theodore Roosevelt is generally considered to be more important for progressive reform due to his strong leadership and advocacy for a wide range of progressive causes. However, Taft also played a significant role in the progressive reform movement and his contributions should not be overlooked.