In October 1962, the world had already experienced two world wars, and a third appeared imminent.

The communist superpower of the Soviet Union had installed nuclear missiles on the island of Cuba, its ally, just 180 kilometers (112 miles) from the US mainland. America felt threatened and imposed a naval blockade.

After an American plane was shot down, many feared the worst. But at the last moment, the Soviet leader, Nikita Khrushchev, announced on Radio Moscow that Soviet nuclear weapons would be withdrawn from Cuba. The world breathed a sigh of relief.

Profound shock at how close they had come to disaster led both sides to think about confidence-building measures despite and indeed because of their enmity. They agreed to set up a direct communications link between the capitals of Washington and Moscow.

Not a red telephone

The hotline between Washington and Moscow came into operation on August 30, 1963, 10 months after the Cuban Missile Crisis. The so-called "red telephone" was not, in fact, an actual phone but a telex machine that sent written messages. This technology was already old-fashioned at the time.

"However, unlike a telephone, it couldn't be tapped," the historian Bernd Greiner explained in an interview with DW.

This was very important to both superpowers. "They wanted to make sure that no other party, whoever it might be, would be able to listen in to their communications," said Greiner.

The first test sentence sent from the US to the USSR sounds cryptic: "The quick brown fox jumped over the lazy dog 1234567890." What was its significance? It contains every letter of the English alphabet and all the numerical digits.

'Signal to reassure the world'

Initially, the hotline was not a telephone, let alone a red one, as depicted in various movies. Greiner, an Americanist and expert on the Cold War, describes its establishment as symbolic.

"It was an external signal to reassure the world that they had understood the value of bilateral emergency communication and that they didn't want to let things go as far as they had in that perilous situation in the fall of 1962."

Greiner quotes the then US president, John F. Kennedy, and his secretary of defense, Robert McNamara, as saying they came up against the limits of their scope for action. The lesson learned from the 1962 missile crisis was that it had not been managed: The outcome depended on chance and the other side's goodwill. It was, therefore, imperative to find other means and forms of communication.

Reaching for the telephone

The hotline was seldom used in its original form as a telex. "It was activated a few times for testing, but they did not resort to it in any acute decision-making situations," says Greiner.

Whenever there seemed to be a severe threat to world peace, it was the classic telephone leaders reached for — during the Six-Day War between Israel and several Arab countries in 1967, for example, and again during the Yom Kippur War in 1973. On both occasions, there was a risk that the conflict would trigger a global crisis, as the US supported Israel, and the Soviet Union was on the side of the Arabs.

The world changes, and so does the hotline

In those dramatic times, the antiquated telex was replaced by a satellite phone. Then, with the fall of the Berlin Wall in 1989, the end of the communist dictatorships in Eastern Europe and the collapse of the Soviet Union in 1991, an early warning system between Washington and Moscow — now the capital of Russia rather than the USSR — began to appear superfluous.

Furthermore, technological innovations, especially the Internet, have created alternatives for rapid and secure communication. The direct link between Washington and Moscow has run on state-of-the-art technology for decades. Channels of communication for use in crisis situations also exist between other capitals worldwide.

The "hotline" is still popular as an early warning system. One would assume that the "red telephone" would have been ringing off the wall since Russia invaded Ukraine in February 2022. However, it is hard for outsiders to assess whether or not the hotline has, in fact, been used.

"We don't know," says Bernd Greiner. "This form of communication is naturally not disclosed."

Less communication than during the Cold War?

According to Greiner, US President Joe Biden is known to have spoken by phone on a few occasions with his Russian counterpart, Vladimir Putin.

"But what happens beyond that in terms of contact at the mid-level or the military level is outside our knowledge," he said.

Greiner, who until 2018 was the head of the Berlin Center for Cold War Studies, doubts that any hotline can help in the current war in Ukraine.

"The problem is that the established communication, between the armed forces in particular but also between diplomats, has virtually broken off. At those levels, there is a sort of silence," said the historian. "This is what differentiates the situation we are experiencing today, against the backdrop of the war in Ukraine, from the situation at even the height of the Cold War" — when the ruling powers in Washington and Moscow decided to set up the hotline.

This article has been translated from German.