What was the red phone hot line?

This was a direct phone connection between Washington DC and Moscow to enable the Soviet Premier and the US President to speak to each other immediately and presumably to prevent nuclear war. It was instituted in 1963.

In the beginning it was an important way to speed up communications because there was an agreed encryption making secure communications faster, but later it was mostly a Public Relations ploy, because, while the line worked, regular phone lines would have worked just as well and normal channels of communicating through diplomats on site would probably worked better.

It was only used once in 1967 to discuss the relative positions of the Soviet and US Fleets in the Mediterranean during the 6-day war.