Roosevelt took office as vice president in 1901 and assumed the presidency at age 42 after McKinley was assassinated the following September. He remains the youngest person to become President of the United States. Roosevelt was a leader of the progressive movement and championed his "Square Deal" domestic policies, promising the average citizen fairness, breaking of trusts, regulation of railroads, and pure food and drugs. He prioritized conservation and established national parks, forests, and monuments intended to preserve the nation's natural resources. In foreign policy, he focused on Central America where he began construction of the Panama Canal. He expanded the Navy and sent the Great White Fleet on a world tour to project American naval power. His successful efforts to broker the end of the Russo-Japanese War won him the 1906 Nobel Peace Prize. Roosevelt was elected to a full term in 1904 and continued to promote progressive policies. He groomed his close friend William Howard Taft to succeed him in the 1908 presidential election.