Theodore Roosevelt helped lead American to it eventually place as a world power with a foreign policy based in three fundamental principals;
1) Broadly conceived U.S. interest: Roosevelt fought to reduce tariffs on U.S. goods and well as He also sought to block European attempts at getting involved in the Western Hemisphere by announcing the Roosevelt Corollary, which said the U.S. would intervene if any country near us defaulted on debts. Roosevelt also wanted to build the Panama Canal, and when the country of Columbia refused to allow this to happen, Roosevelt backed a Panamanian revolution in exchange for rights to the canal zone.
2) Strengthening the U.S armed forces: At the end of the 19th century, the U.S. had the smallest armed forces of any major nation. The fact that volunteers fought the majority of the Spanish-American war led Roosevelt to make sweeping reforms. War colleges were expanded, a European-style general staff for the army. He rotated out officers that were ineffective and promoted those who he felt were more up to the task. He also began building up the navy, and by 1907 we had the third largest navy in the world.
3) Making the U.S. a global presence: Roosevelt worked hard to sell the image of the U.S. as a major global player. He helped negotiate peace during the Russo-Japanese War and attended the Algeciras Conference along with 12 other nations.
Roosevelt wrote The naval war of 1812, a book about how a trading nation must have a navy. Even if he had not become president, his book would have influenced American foreign policy.