President Ronald Reagan gave the go ahead for Operation Fury. It following a a bloody coup by Cuban-trained military who executed Prime Minister Maurice Bishop; he was killed by the People’s Revolutionary Army firing squad.
Why did the US go on? The US did not own Grenada. Indeed, this former British colony was part of the Commonwealth. British Prime Minister Margaret Thatcher tried to dissuade Reagan from attacking. Reagan reminded Thatcher that the US had helped Britain in the Falklands War.
This was the duo’s one serious argument. Maggie was overruled.
Reagan noted that the revolutionary government had began to develop a runway that could have been used as a Cuban or Soviet airbase.
Also, the Organisation of Eastern Caribbean States (OECS) had invited US intervention. If this was an illegal war, as the UN decreed it was, it was none not unpopular with all locals on the islands, with reports of them cheering as their army was routed.