Hair-trigger alert is a nuclear weapons policy designed to ensure U.S. retaliation should there even be a nuclear attack on the United States. When a nuclear missile is launched there are only 15-45 minutes to decide how to react. Once the weapon blows up it is too late.
For this reason, during the Cold War the U.S. and the USSR enacted their hair-trigger alert Policies. This means that once a decision is reached to fire a nuclear weapon the weapon could be launched in under 5 minutes. The sole purpose of this policy is to ensure that in the event of a nuclear strike, both countries would sustain critical losses.
Hair-trigger alert policies mean relying on sometimes inaccurate sources of information (radar) to make very quick decisions (15-45 minutes). There is a lot of potential for errors. Furthermore, acknowledging that these missiles can only be launched after government approval is given, a missile that can be launched within five minutes is very exposed to unauthorized and accidental launches.
A full out nuclear war with first use policy, meaning that all nations involved are able to launch their nuclear weapons, could wipe out all life on Earth. This is not an exaggeration and as difficult to believe as it is, we are minutes away from that catastrophe. The United States must end its hair-trigger alert policy and encourage other nations to do so as well.