Theodore Roosevelt became president in September 1901 after the assassination of William McKinley. Although he had been vice president under McKinley, Roosevelt did not share McKinley’s conservative, pro-business policies. Instead, as president, Roosevelt advanced aggressive political reforms, including the heavy regulation of business. Known as the “trust-buster,” Roosevelt was the first president to successfully invoke the Sherman Antitrust Act against monopolies and continued to restrict businesses throughout his presidency. His reforms greatly influenced economic, environmental, and international affairs as well. Roosevelt’s platform became known as the “Square Deal” because he vowed not to favor any group of Americans but to be fair to all.

Roosevelt was committed to addressing the problems of labor and corporate activity. Unlike his predecessors, Roosevelt defended the right of labor to organize, and eschewed the use of federal troops to put down strikes. In 1902, he intervened in a United Mine Workers Strike and helped labor get management to agree to binding arbitration. The arbitrators awarded the miners a wage increase and a shortened workday.

Roosevelt also worked to restrict the power of big business by breaking up a monopoly. In his administration’s first trust-busting case, his attorney general filed suit against the Northern Securities Company, a railroad holding company, for violating the Sherman Antitrust Act, which had not been successfully used against monopolies since its passage in 1890. After this case, though, the Act became an extremely important tool for government regulation of corporations. In 1904, the Supreme Court ordered that the Northern Securities Company be dissolved, a decision that launched a series of antitrust suits. In all, the Roosevelt administration filed forty-three trust-busting suits.

After winning reelection in 1904, Roosevelt traded sporadic bursts of trust-busting for more permanent regulation. He successfully negotiated the passage of the Hepburn Act in 1906, which empowered the Interstate Commerce Commission (ICC), a previously weak agency, to set maximum railroad rates and inspect railroad companies’ financial records.

Responding to the muckrakers’ exposés on the unsanitary conditions in food plants and the dangerous ingredients in foods and medicines, Roosevelt endorsed the Pure Food and Drug Act and the Meat Inspection Act, both passed in 1906. The first act prohibited the sale of adulterated or inaccurately labeled foods and medicines, and the second established federal regulations for meatpackers and a system of inspection.

The early twentieth century also saw a rise in concern for the environment. Those who supported conservation and protection of wilderness sites were called preservationists. Preservationists were often in conflict with business interests who saw the wilderness in terms of resources and space for commercial and residential development. Roosevelt was at heart a preservationist, but understood the need for compromise. He achieved this compromise through his conservation program, which provided for the regulated use of the nation’s wilderness. Roosevelt designated 200 million acres as national forests, mineral reserves, and potential waterpower sites, and added five national parks and eighteen national monuments to the list of protected lands. In 1908 Roosevelt created the National Conservation Commission to inventory the nation’s resources and manage their use more efficiently.

Roosevelt summed up his approach to foreign policy in a single sentence: “Speak softly and carry a big stick.” Having become president shortly after the American victory in the Spanish-American War, Roosevelt was confident in America’s status as a major international power. His goal to maintain that status through aggressive tactics was dubbed “big stick” diplomacy.

Roosevelt’s most notable achievement in foreign policy was the building of the Panama Canal, an artificial waterway stretching through the isthmus of Panama, which was then part of Colombia. Since the canal connected the Atlantic and Pacific oceans and vastly shortened shipping routes, Roosevelt saw its creation as vitally important to American economic and maritime interests. When the Colombian government first rejected America’s offer to lease the land and build the canal for over $10 million, Roosevelt helped engineer a revolution on the isthmus. The revolution erupted in 1903, and the new Panamanian government that took power proved to be much more cooperative with the United States. The new government granted the U.S. permanent possession of the ten-mile-wide strip of land across Panama on the same financial terms rejected earlier by Colombia. Construction on the canal began in 1906, and it opened in 1914.

Roosevelt’s intervention in Panama was indicative of his entire attitude toward Latin America, where he asserted the Roosevelt Corollary to the Monroe Doctrine. In 1904, with several European nations poised to invade the Dominican Republic, Roosevelt declared that the United States, not Europe, should dominate Latin America, and that although the U.S. had no expansionist intentions, any “chronic wrongdoing” by a Latin American nation would justify U.S. intervention as a global policeman. (Remember that the Monroe Doctrine had warned Europeans not to intervene in Latin America; the Roosevelt Corollary maintained this warning, and asserted that the U.S. alone could intervene.) During Roosevelt’s presidency, the U.S. invoked the Roosevelt Corollary repeatedly as justification for its involvement in the affairs of the Dominican Republic, Haiti, Venezuela, Nicaragua, and Cuba.

Roosevelt also involved himself in the affairs of Asia after the Russo-Japanese War broke out in 1904. Concerned about maintaining the balance of power between nations, Roosevelt invited delegates from Russia and Japan to the U.S. for a peace conference in 1905 that resulted in the signing of a treaty. Roosevelt received the Nobel Peace Prize for his actions. In an effort to discourage further trouble in Asia, Roosevelt sent sixteen new, gleaming white battleships, dubbed “the Great White Fleet,” to Asian ports and elsewhere around the world.