Deterrence in general means threatening your enemy with retaliation if that enemy attacks you first,
so that the enemy will decide it's not worth it and the war won't happen.
The primary purpose is to prevent war, to maintain peace and to keep things the way they are.
You need to threaten something that's more painful to the opponent
than what you're trying to prevent them from doing,
and you have to threaten it in a way that
they will believe you'll carry out the threat.
So the threat has to be severe and credible.
Often deterrence is
accompanied with reassurance, and this is
especially important in extended
deterrence relationships involving allies.
Extended deterrence means, I am
going to threaten an opponent to keep
them from doing something to someone else.
You can never be sure whether deterrence has worked unless it fails.
If your enemy attacks you, you know it
didn't work; but if your enemy doesn't
attack you - is that because your
deterrent worked just right, or because
the enemy never wanted to attack you in the first place?
If deterrence works, you get what you want without a war.
The disadvantage is that it depends on the
credibility of the threat, which depends
on the perception of the enemy about what you might do in the future, but aren't now.
And this business of depending on the perceptions of leaders
in another society has often worried people.
Deterrence takes place all the time, and
has taken place for centuries, if not millennia.
It became a more explicit concept after 1945,
with the coming of nuclear weapons and the prospect that a World War III
would destroy most of civilization.
Nuclear weapons pose a variety of interesting problems for
deterrence because when you're promising
to do something that could be suicidal -
starting a nuclear war with another superpower, for example -
the credibility issue becomes very complicated.
They have to believe that we would carry out the retaliatory threat,
and after all we're talking about a situation now in which
the United States has been largely destroyed.
Some people have argued that
in today's world deterrence just isn't
going to work the way we relied upon it to work during the Cold War.
One reason is, they argue that there are rogue
states like North Korea, led by irrational leaders who can't be relied upon to
respond sensibly to the threats that we are making.
Other people argue the terrorism is much harder to deter.
Terrorists are often suicidal, and you
can't very well deter someone with the threat of death and retaliation
if they want to die anyway.
And they don't have a return address for their attack,
so, therefore, we don't know who to retaliate against.
Defenders of deterrence argue
that even in the current environment, the concept is still important.
Most of all, it's becoming an issue again potentially
in regard to Russia and China.
Russian intervention in Ukraine, annexation of Crimea, has alarmed many in the West;
It has raised the question about whether
military conflict in Europe between Russia and the West might be possible again.
So, reconstructing a clear
deterrence policy for this new situation in Europe is what a lot of people in
Washington are staying up late about.
China is flexing its muscles and asserting rights over certain
territories and ocean areas; and what
strategy to develop to deter China from expanding further,
or making even greater claims,
hasn't been made clear yet.