High Quality Content by WIKIPEDIA articles! The Platt Amendment was a rider appended to the Army Appropriations Act presented to the U.S. Senate by Connecticut Republican Senator Orville H. Platt (1827-1905) replacing the earlier Teller Amendment. The amendment stipulated the conditions for the withdrawal of United States troops remaining in Cuba since the Spanish-American War, and defined the terms of Cuban-U.S. relations until the 1934 Treaty of Relations. The Amendment ensured U.S. involvement in Cuban affairs, both foreign and domestic, and gave legal standing to U.S. claims to certain economic and military territories on the island including Guantanamo Bay Naval Base. The Platt Amendment came in 1899 from the United States to expand its sphere of influence in Cuba and protect American investments by pacifying the state. During the Spanish-American War the United States maintained a military arsenal in Cuba to protect US holdings and mediate Spanish-Cuban relations.