Final answer:
President Theodore Roosevelt was called a trustbuster because he supported legal action against business monopolies.
Step-by-step explanation:
President Theodore Roosevelt was called a trustbuster because he supported legal action against business monopolies. During his presidency from 1901 to 1909, Roosevelt was known for actively taking on large corporations and enforcing antitrust laws. He believed in promoting fair competition in the economy and breaking up monopolies that hindered it. Some of the notable cases during his presidency include the breakup of the Northern Securities Company and the initiation of legal proceedings against Standard Oil.
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