More than three decades ago, U.S. President Ronald Reagan authorized Operation Urgent Fury, which led to American troops briefly capturing the tiny Caribbean nation of Grenada in the space of weeks. Political chaos on the island, spurred by the ousting and execution of its leftist leader by more radical elements, gave Washington a pretext to intervene in a country it feared was becoming a Cuban satellite and a new front in the Cold War with the Soviet Union.

The problem, though, was that Grenada is a former British colony and member of the British Commonwealth. Britain's then-leader, Prime Minister Margaret Thatcher, had not been in favor of the U.S. invasion, which was planned and executed in tremendous secrecy. The Iron Lady was angry that her concerns were not heeded by the White House.

According to her memoirs, Thatcher, who died in 2013, sent Reagan a message in the early hours of Oct. 25, 1983, as the U.S. invasion was underway. She said she was "deeply disturbed" by the American escalation. "This action will be seen as intervention by a Western country in the internal affairs of a small independent nation, however unattractive its regime," Thatcher said.

In her memoirs, Thatcher says Reagan, in a subsequent phone call, told her that the moment had already passed for the Americans to turn back. Now, a recording of that phone call has emerged. The U.S. president can be heard, with a contrite tone, placating a terse Thatcher. You can read the full transcript of their conversation here.

Members of the U.S. Armed Forces plan their operations in Grenada on Oct. 28, 1983. (AP Photo/Peter D. Sundberg)

"We regret very much the embarrassment caused you," Reagan said, attributing his government's swift decision to invade on fears of leaks within Washington. No American journalists were taken with the U.S. invasion force, a matter that proved controversial in the incident's aftermath.

U.S. armed forces were able to overwhelm Grenada's military and a detachment of Cuban servicemen with minimal casualties within two weeks. There was an element of farce to the proceedings: American troops were inhibited by a lack of adequate intelligence on the country, and at some points had to resort to tourist maps to figure out the lay of the land.

Fewer than 100 combatants were killed in clashes. With a lopsided vote, the U.N. General Assembly denounced the invasion as a violation of international law; Reagan blithely quipped that "it didn't upset my breakfast at all." The United States installed an interim government that eventually held elections the following year. The threat of further communist inroads in the country of 90,000 people was neutralized.

Two U.S. soldiers stand guard over three Grenadian prisoners in St. George's, Grenada in Oct. 1983. (AP Photo)

A host of questions remain regarding the legitimacy of the invasion and the real reasons that it took place. Veteran foreign correspondent Stephen Kinzer sums up what Reagan argued in public, which included a largely inflated scare over the safety of a group of American medical students studying on the island.

First, they depicted Grenada's regime as murderous, anti-American and supported by Cuba. This was true, but it did not make Grenada a threat to the United States. Second, they said they needed to protect the lives of American students, although the students did not appear to be in danger. Third, they produced a letter signed by the governor general of Grenada, Paul Scoon, asking for intervention. It later turned out that the letter had been written in Washington, backdated and delivered to Scoon to sign after the invasion began.

In his phone call with Thatcher, Reagan makes clear how much communist Cuba's hand in Grenada influenced his decision. The immediate impetus for the invasion was the coup and assassination of Grenadian leader Maurice Bishop, a Marxist revolutionary turned prime minister whose apparent desire for rapprochement with Washington incensed more radical figures within the regime. Here's Reagan on the phone with Thatcher:

We think [Bishop] was murdered because he began to make some noises as if he would like to get better acquainted with us. He no more got back on the island -- he was here and visited our State Department -- and he was murdered. The people who murdered him him are even further over in the Cuban camp. So things would be worse, not better, for the people on Grenada.

Reagan and Thatcher then discuss the importance of other Caribbean leaders backing the regime change in Grenada so that Washington's actions don't appear to be so unilateral. "We want to put [a group of Caribbean statesmen] out ahead in helping with the restoration of a government, so there will be no taint of big old Uncle Sam trying to impose a government on them," Reagan said.

President Ronald Reagan and British Prime Minister Margaret Thatcher ride an electric cart at Camp David, Maryland, Dec. 22, 1984. (Bill Rowntree/AP)

By the end of the phone call, Reagan seems to have Thatcher's assent. The two were inveterate Cold Warriors and shared a vision of foreign policy that, on occasion, led them down tricky moral rabbit holes -- both Thatcher and Reagan, for example, initially backed South Africa's apartheid regime out of distrust of the supposed communism of those opposed to it.

The invasion of Grenada came just days after a massive suicide bombing on a U.S. military barracks in Beirut led to the deaths of 241 American service members. Operation Urgent Fury -- which was neither that urgent nor particularly furious -- gave the White House an opportunity to restore a bit of its prestige. A detachment of Marines bound to join peacekeeping forces in Lebanon was even rerouted to participate in the invasion.

One of the biggest cheerleaders of the invasion was Richard B. Cheney, then a congressman from Wyoming and later vice president. Despite the opposition of a number of Democratic politicians and concerned academics, Cheney argued that U.S. restoration of democracy in Grenada was an important feather in Washington's cap.

"A lot of folks around the world feel we are more steady and reliable than heretofore," he said at the time.

Twenty years later, Cheney and his allies would trot out a similar line about the role of American leadership in the buildup to the U.S. invasion of Iraq. But it will take much more than a friendly phone call to hush those who would disagree, or sweep under the rug some of the disastrous consequences of yet another display of unilateral American might.