Progressivism, yo.

The government fought against monopolies by trying to destory trusts. William H. Taft, also known as the "trustbuster", wanted to destory all monopolies. This encluded monopolies on the train transportation system. Tycoons over the railroad were able to control the price of shipping, manipulating how much farmers had to pay to ship their goods. Farmers lost massive profits during this, making many of them have to resosrt to sharecropping. Regulating monopolies was essiential to keep the middle and lower class, or anyone not envolved in monopolies, from encountering massive debt. My regulating monopolies, Taft was truly controlling how well the country would progress. However, the Panic of 1907 occured, deeming his attempts slightly unsuccessful. Woodrow Wilson wanted to expand "The New Freedom", or expand democracy. He enchanced democracy, rather than change it to something new. Roosevelt's attempt to pereserve the land, yet make cheaper engery sources was somewhat successful, as dams currently reside to do so, yet perserving the land in some of these efforts were not.
So, in all, the three leaders of Progressivism were mostly not successful, but they did have some impact on the progress of America.