In 1861, Dominican military commander and royalist politician Pedro Santana signed a pact with the Spanish Crown and reverted the Dominican nation to colonial status. Spain was wary at first, but with the U.S. occupied with its own civil war, it felt it had an opportunity to reassert control in Latin America. On March 18, 1861, the Spanish annexation of the Dominican Republic was announced. The end of the American Civil War in 1865 and the re-assertion of the Monroe Doctrine by the United States, which was no longer involved in internal conflict, prompted the evacuation of Spanish forces back to Cuba that same year.