Final answer:
The Progressive Party, established in 1912 and led by Theodore Roosevelt, targeted trusts and monopolies to reform government and restore competitive markets.
Step-by-step explanation:
The political party that made trusts and monopolies a target during the early 20th century was the Progressive Party. Formed in 1912 by former President Theodore Roosevelt, the Progressive Party aimed to address issues resulting from the United States' transformation to an urbanized, industrial nation dominated by large corporate interests. Their platform included a commitment to breaking the power of large business entities, which they perceived as exercising too much influence over industry and finance. The Progressives sought to make the government more responsive to the will of the people and believed in aggressive measures like antitrust laws to dissolve monopolies and restore competitive markets.