Bay of Pigs fiasco. That "invasion" was a sign of what may come, or so the Soviets believed. They thought, even though the U.S. didn't follow through like they said they would, they had the aggression to do something.The Soviet fear of a Cuban invasion was a "grounded" fear. Kennedy rejected military advice for a full-scale surprise attack on Cuba. Instead, Kennedy issued and ultimatum to the USSR and Castro on October 22. He declared a "quarantine", or a naval blockade of Cuba. He demanded, to have the blockade removed they would have to withdraw all offensive missiles and military equipment.This demand lead to a severe rise in fear and tension. Kennedy decided that the military had to be alert. So he decided to raise the armed forces to defense condition 3. Defense Conditions were a way to measure the threat of nuclear attack. It is more commonly referred to as Def Con. During peacetime the nation is at Defense Condition 5. Def Con 1 is reached only during an all out nuclear holocaust. It was/is necessary to develop a way to measure the level of nuclear awareness because the military needs to be united in the face of nuclear war especially with the capabilities of some nations. It was recognized that the world could be rid of all life with just the press of a button. So at Def Con 3 the military alertness was heightened. Troops at all U.S. bases were running on 12-hour shifts. More aircraft were on standby at all times. If there were normally two aircraft prepped and ready to go then now there were 4 or 5.After 13 days, the Soviet government of Nikita Khrushchev yielded. He agreed to negotiate and compromise. The Soviet government agreed to militarily pull out of Cuba. This meant they would remove missiles and disassemble the launch sites. They also agreed to pull the troops, aircraft, and ships. The U.S. government agreed to remove the blockade and they also agreed to stay out of Cuba. They wouldn't invade or in a...