The closest the United States and Russia ever came to nuclear war
was actually after the Cold War had ended.
One of the theories of how a nuclear war would start is that one side
would launch just a single nuclear missile and detonate it at a high altitude,
thereby creating a powerful electromagnetic pulse.
The electromagnetic pulse would knock out electrical equipment in the enemy country,
and with their radar now blind,
the real attack consisting of hundreds of nuclear missiles would then begin.
On January 25, 1995, the Russian military believed
that such a scenario might be about to unfold.
On this day, the country of Norway launched a rocket
which to Russian radar operators appeared identical
to a United States submarine launched ballistic missile.
President Yeltsin issued an order to all of Russia’s nuclear forces to be on standby
to launch a retaliatory attack on the United States,
and this is the first and only time
that the nuclear brief case of either country has ever been activated.
In general, by the time that a president is notified through the chain of command that a potential incoming nuclear attack has been detected, the president has approximately ten minutes to decide whether or not to launch a retaliatory response.
Note: This assumes launch on warning. (i.e. before impact.)
Time for submarine launched ballistic missile to reach target: 15 minutes.
Although there are many safeguards to prevent an
accidental nuclear launch through malfunctioning equipment,
the systems for detecting incoming missiles are notoriously faulty.
Throughout the cold war,
there were numerous incidents in both the United States
and in the Soviet Union where these systems falsely
indicated that the country was under nuclear attack, when this was not the case.
So far, we have been lucky that these incidents
did not result in a full scale nuclear war.
For example, in the case of the Norwegian rocket incident, Yeltsin decided that it was unlikely that the United States would actually launch a nuclear attack, and he waited long enough for radar operators to determine that the rocket was heading away from Russian airspace.
Though, if the incident had happened during a time of political tension, or if a different leader had been in place, the results might have been very different.
In any case, even if it were possible to hypothetically know with 100% certainty
that the country is about to be hit with incoming nuclear missiles,
the decision to launch a retaliatory nuclear response would not change this outcome.
The principle of mutually assured destruction states that
if your adversary chooses to launch a nuclear attack,
you have no way of preventing your country from being destroyed.
The only decision you have is whether or not to launch your own missiles.
Though, this will not kill the people responsible for giving the orders to launch
the attack, as they are presumably safe in their bomb shelters deep underground.
A retaliatory strike will instead kill millions
who had nothing to do with this decision,
not only in the enemy country,
but all over the world as the result of radioactive fallout,
and the large quantity of dust, smoke, and soot kicked up into the atmosphere
blocking sunlight across much of the planet,
leading to crop failures and global famine.
And even if you do choose to launch a retaliatory strike,
this will not change the fact that your own country will still be destroyed.
Therefore, many senior analysists in the military conclude that
ordering such a nuclear retaliation would always inherently be an irrational response,
even if you hypothetically known with 100% certainty
that your adversary has launched its missiles.
However, these same analysts also conclude that
in order for your nuclear weapons to be an effective deterrent,
your adversary needs to believe that you will, in fact,
order a retaliatory strike if attacked.
But, one of the many unfortunate consequences of nuclear deterrence
is that your adversary can mistakenly think that they are under attack,
as in the case of the Norwegian rocket incident,
and a nuclear war may start by accident.
So far, we have been lucky in that such an event has not occurred.
However, we may not be so lucky over the course of the next several hundred years.
As with the game of Russian roulette, luck has a tendency to eventually run out.
This is actually one of the theories as to why we have
not yet discovered radio transmissions from alien civilizations.
Here on earth, radios and nuclear weapons were invented less than 100 years apart,
which is just the blink of an eye on the cosmic time scale.
Some people believe that throughout the universe,
each time a civilization becomes technologically advanced,
it ends up destroying itself soon afterwards through nuclear war,
and that this is the reason we have not yet detected any alien radio broadcasts.
There are, of course, many other theories,
such as the fact that advanced alien civilizations may be using
forms of communication presently inconceivable to us,
just as radio waves were inconceivable to people living in the Stone Age.
We have no way of knowing what percentage of alien planets throughout the universe
go through a nuclear arms race, as the human race has done here on Earth,
since it is not possible to do statistical analysis on a single data point.
For example, if our only data point is life inside an insane asylum,
then we have no way of knowing that this is not normal,
and we have no point of reference for realizing the
degree to which our situation is well outside the standard statistical deviations.
It could very well be that
most technologically advanced civilizations throughout the universe are peaceful,
and that they look with bewilderment and disbelief
upon the insane asylum which we call Earth.