The Enhanced Defense Cooperation Agreement (EDCA) is an agreement between the United States and the Philippines intended to bolster the American–Philippine alliance. The agreement allows the United States to rotate troops into the Philippines for extended stays and allows the United States to build and operate facilities on Philippine bases for both American and Philippine forces. The U.S. is not allowed to establish any permanent military bases. The Philippines have personnel access to American ships and planes. The EDCA is a supplemental agreement to the previous Visiting Forces Agreement. The agreement was signed by Philippine Defense Secretary Voltaire Gazmin and U.S. Ambassador to the Philippines Philip Goldberg in Manila on April 28, 2014, preceding a visit by U.S. President Barack Obama that same day. On January 12, 2016, the Philippine Supreme Court upheld the agreement's constitutionality in a 10–4 vote. On July 26, 2016, the Philippine Supreme Court ruled with finality that the agreement is constitutional. Evan Medeiros, the U.S. National Security Council's senior director for Asian affairs was quoted in The Washington Post as saying, "This is the most significant defense agreement that we have concluded with the Philippines in decades." Background For more than a century, the Philippines has been important to American defense strategy. Currently, the Philippines is a "major non-NATO ally" of the United States. The U.S. acquired the Philippines from Spain after the Spanish–American War of 1898 and then fought the Philippine–American War against Philippine revolutionaries to secure their rule. After both wars, the Philippines was a territory of the United States from 1898 to 1946. The United States granted the Philippines independence in 1946. The Mutual Defense Treaty was signed in 1951 and ratified in 1952 by the governments of the United States and the Philippines. The purpose of the Treaty was to "strengthen the fabric of peace" in the Pacific, by formally adopting an agreement to defend each other's territory in the case of external attack. In line with this treaty, the United States maintained several military bases in the Philippines, including Subic Bay Naval Base and the Clark Air Base. In 1992, the bases closed after the Philippine Senate rejected, by a close vote, a treaty that would have extended the bases' lease. The treaty was rejected because of U.S. reluctance to set a firm time frame for troop withdrawal and to guarantee that no nuclear weapons would pass through the base.