11 August 1984 – President Ronald Reagan joked during a radio soundcheck that he had “signed legislation that would outlaw Russia forever. We begin bombing in 5 min. ” Though the joke was not broadcast live (contrary to some accounts) when word of it spread, the Soviet Army was put on high alert for about 30 min. (1)
Cold War: Ronald Reagan jokes about ‘bombing’ Russia in 1984
Source: (1) Wikipedia/Portal: Aviation Anniversaries