For context:

• Grenada is a small nation, but its alignment with the USSR and Cuba provided strategic advantages to those nations. Grenada was on the opposite side of the Caribbean from Cuba. The construction of an airfield on the island by Cuban soldiers threatened to establish a real strategic threat to commerce and military operations in the Caribbean. A Cuban military presence on Grenada would also allow Cuba to ramp up its military activities in Africa, by shaving over 3,000 miles off a round trip.

• The US government had established a precedent of financial, covert and military intervention (Guatemala, El Salvador, Nicaragua, Colombia) against any Cuba-aligned government in the Americas.

• Several hundred U.S. citizens attended the St. George's University School of Medicine on Grenada, providing a concentrated group of potential hostages.

• Tensions around the world were high in late 1983; the Soviets shot down a civilian airliner on September 1, killing 269 people. President Reagan adopted a belligerent stance in reaction. As a result, the U.S. military deployed forces in the eastern Caribbean to threaten Grenada. (The intervention in Lebanon was a sideshow to the larger confrontation between the superpowers.)

These actions created the crisis of October 1983 in Grenada. Leftist elements within the government pressed Prime Minister Bishop to strengthen the military and invite stronger Cuban support. Bishop refused, fearing this would provoke an intervention. He was removed from power on October 12. Street protests broke out. Loyalists broke Bishop and other members of his government out of house arrest, but the new junta (led by Deputy Prime Minister Bernard Coard and military commander Gen. Hudson Austin) suppressed the loyalist revolt on October 19, killing 10 demonstrators. Later that night, Bishop and seven of his followers were executed. General Austin assumed command of a new military government.

The next day, the Joint Chiefs ordered the deployment of combat-ready troops within striking range of Grenada and the U.S. government shepherded a joint declaration through the Organization of Eastern Caribbean States on October 21, calling for a multinational intervention to restore order. The next day, the British Governor-General of Grenada formally requested an intervention. The same day, Castro ordered his troops on Grenada to fire in self-defense only.

Also that day, President Reagan met with the Joint Chiefs and was informed that Grenada's new military government was calling up 2,000 reservists. The final straw was the new junta's refusal to allow the American students on Grenada to evacuate. Reagan approved the military proposal for a massive attack on October 25.

It wasn't until October 23 that the Beirut barracks was bombed, and preparations for the invasion were not paused as a result.

Would the United States have intervened without Coard and Austin's coup? Unlikely to say the least. There was no broad diplomatic consensus, and if Bishop had stayed in power the Lebanon crisis would have made U.S. decision-makers more gunshy. The United States had other economic measures it could have deployed. For example, tuition from the St. George's medical school represented 10 percent of Grenada's GNP - this was a large part of Bishop's reluctance to adopt a more confrontational posture. Ordering U.S. citizens to evacuate from the school was the American ace in the hole - and in a more prolonged contest it certainly would have been threatened to extract concessions.

Sources:

Cole, Ronald H. Operation Urgent Fury: The Planning and Execution of Joint Operations in Grenada, 12 October–2 November 1983. Washington, D.C.: Joint History Office, Office of the Joint Chiefs of Staff, 1997.

Stewart, Richard W., and Edgar F. Raines. Operation Urgent Fury: The Invasion of Grenada, October 1983. Washington, D.C.: U.S. Army Center of Military History, 2008.