What was Reagan trying to keep from happening in Nicaragua?

President Ronald Reagan aimed to prevent the establishment of a Marxist government in Nicaragua, which he viewed as a threat to U.S. interests and regional stability in Central America. His administration supported the Contras, a rebel group fighting against the Sandinista government, in an effort to undermine the leftist regime. Reagan believed that a communist foothold in Nicaragua could lead to the spread of socialism throughout the region, prompting his active involvement in the conflict.