Theodore Roosevelt and the Birth of American Global Ambition

Theodore Roosevelt became president in September 1901 at forty-two years old, following the assassination of William McKinley. He was the youngest person to hold the office, and he arrived with a vision of American power that was unlike anything his predecessors had articulated. The United States, in Roosevelt's view, was not merely a continental republic that should mind its own affairs. It was a great power with global responsibilities, and it should conduct itself accordingly.

Roosevelt had come to this view through a combination of intellectual conviction and personal temperament. He had read Alfred Thayer Mahan's The Influence of Sea Power Upon History, which argued that naval power was the foundation of national greatness. He believed in what he called the strenuous life — a philosophy of vigorous action, physical and moral courage, and national vitality. He had a romantic attachment to military glory that he had partly satisfied by leading the Rough Riders up Kettle Hill during the Spanish-American War of 1898.

That war had been transformative for the country. In a few months of fighting, the United States defeated Spain, acquired Puerto Rico and Guam, purchased the Philippines for twenty million dollars, and established a protectorate over Cuba. In one stroke, America had become a colonial power in both the Caribbean and the Pacific. The debate about whether this was consistent with American democratic principles was fierce and unresolved.

Roosevelt's foreign policy rested on what became known as the Roosevelt Corollary to the Monroe Doctrine. In 1904, responding to concerns about European powers intervening in Latin American countries that had defaulted on debts, Roosevelt declared that the United States would serve as an international police power in the Western Hemisphere. This was a significant escalation of American ambition — not merely keeping Europe out but asserting the right to intervene in Latin American affairs directly.

The Panama Canal was Roosevelt's most concrete foreign policy achievement and his most revealing one. When Colombia refused to ratify a treaty allowing canal construction through what is now Panama, Roosevelt encouraged a Panamanian independence movement, sent warships to prevent Colombian troops from suppressing it, and recognized the new nation within three days of its independence. He was unapologetic. The canal, he believed, was a necessity for American naval power and commerce, and he had made it happen.

Domestically, Roosevelt was equally consequential. His antitrust actions against Northern Securities and Standard Oil established that the federal government could and would regulate the largest corporations. His conservation policies set aside hundreds of millions of acres of public land. His understanding of the presidency as a bully pulpit — a platform for leadership and persuasion rather than just execution — permanently expanded what Americans expected from the office.

Roosevelt did not create American global ambition. But he gave it an institutional form and a moral vocabulary. After Roosevelt, the question was not whether America would be a world power but how that power would be used.