Theodore Roosevelt (1858-1919) was the 26th president of the United States and a proponent of the "New Nationalist" variety of Progressivism. A master of populist rhetoric and public charm, Roosevelt quickly tapped into the widespread fervor for reform. His administration pursued some widely publicized antitrust cases against large companies like Northern Securities and the Swift Beef Trust, but for all his aggressive rhetoric, Roosevelt actually went after fewer monopolies than his successor, William Howard Taft.
Throughout his administration, Roosevelt attempted to strike a balance between employers and employees in labor disputes and pledged to give Americans a "Square Deal" that prized a person's character above his class. He made notable strides in the cause of conservationism, dedicating many National Parks and restricting private development on government lands. After voluntarily stepping down from office in 1908, Roosevelt became increasingly disenchanted with William Howard Taft, his hand-picked successor to the presidency. He challenged Taft for the Republican nomination in 1912, and when he lost, he started his own Progressive (or "Bull Moose") Party, positioning himself as the more aggressive trust-busting candidate. While Roosevelt's New Nationalist policy accepted economic concentration as an inevitability in America's rapidly industrializing society, Democrat Woodrow Wilson pledged to destroy the trusts altogether in order to restore competition to the marketplace. Roosevelt lost the election but remained a legendary figure in American political history.