What is Theodore Roosevelt's greatest contribution to the progressive movement?

Theodore Roosevelt's greatest contribution to the progressive movement was his vigorous advocacy for social reform and regulation of big business. He championed policies that promoted consumer protection, such as the Pure Food and Drug Act and the Meat Inspection Act, which aimed to ensure the safety of food and medicines. Additionally, he was a strong proponent of conservation, establishing national parks and forests to protect Natural Resources. Roosevelt’s leadership helped to galvanize public support for progressive ideals and set a precedent for future reforms.