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.
In 1898, Roosevelt formed a military regiment—the Rough Riders—to fight against Spain in Cuba. He fashioned himself a "natural leader" of the regiment, a group that included Ivy Leaguers, miners, cowboys, Native Americans, sons of Confederate veterans, and African-Americans. Fighting in Cuba for only a few months before Spain surrendered to the U.S., Roosevelt and his Rough Riders returned, revered as heroes. Roosevelt channeled his new military fame into a successful political career.