In 1979 a bloodless coup, led by the revolutionary Maurice Bishop, toppled the government of Grenada to establish a communist society. Under Bishop, Grenada began construction of an international airport with the help of Cuba. To begin to establish a case for invasion, seven months before the operation began, Ronald Reagan pointed to this airport and several other sites as evidence of the potential threat posed by Grenada towards the United States. Reagan accused Grenada of constructing facilities to aid a Soviet/Cuban military build-up in the Caribbean.
Prime Minister Bishop went to Washington, D.C., to dispel these fears, but his government was later overthrown in a violent coup on October 13 in which a Marxist-influenced group within the Grenadian Army, controlled by former Deputy Prime Minister Bernard Coard, seized power. The combination of a bloody seizure of power by a Marxist group within the US "sphere of influence" and the presence of almost 600 American medical students combined to convince the United States to act. The USA had also just suffered the loss of 240 Marines in a suicide bombing of their barracks in Lebanon on October 23.
The governor-general of the island appealed to the Organization of Eastern Caribbean States (OECS) to remove the coup leaders from power. The OECS appealed to the United States, Barbados and Jamaica to assist them.
Bernard Gewertzman demolished those reasons in an article in the October 29 issue of the New York Times: "The wording of the formal request, however, was drafted in Washington and conveyed to the Caribbean leaders by special American emissaries. Both Cuba and Grenada, when they saw that American ships were heading for Grenada, sent urgent messages promising that American students were safe and urging that an invasion not occur. [...] There is no indication that the Administration made a determined effort to evacuate the Americans peacefully. [...] Officials have acknowledged that there was no inclination to try to negotiate with the Grenadian authorities".
The invasion did not receive the support of the British government, who were put out by the fact that the United States had neglected to inform them of their intentions, despite the fact that the Queen Elizabeth II was the head of state and the nominal "Queen of Grenada".
Fighting continued for several days and the total number of American troops reached some 7,000 along with 300 troops from the assisting neighboring islands of Antigua, Barbados, Dominica, Jamaica, St Lucia and St Vincent. They encountered soldiers and advisors from various countries including about 1,200 Grenadians, 780 Cubans, 49 Soviets, 24 North Koreans, 16 East Germans, 14 Bulgarians, and 3 or 4 Libyans. By mid-December, the American troops withdrew after a new government was appointed by the governor-general.
In 1984 Reagan often quipped that Grenada had to be invaded because it was the world's largest producer of nutmeg, and "you can't make eggnog without nutmeg."