Military deterrence has been credited with preventing large-scale conflict, particularly since the Second World War. The great powers have not attacked each other directly since the policy was instituted.
At first sight, the ability to threaten would appear to be an argument for having overwhelming defence forces at one’s disposal, as some writers still urge, but this doesn’t guarantee peace. The overall situation has continued to evolve, and strategic thinking needs to adapt to the changes. Deterrence hasn’t prevented wars during the 70 years since nuclear weapons were first deployed – though arguably it has helped to prevent another world war thus far.
The following sub-sections examine the progression from the doctrine of mutually-assured destruction which characterised Cold-War nuclear deterrence (18.104.22.168), through the inadequacy of that doctrine against asymmetric threats (22.214.171.124), to the continuing use of deterrence as a component of ‘realpolitik’ (126.96.36.199).
 Michael Ledeen, for example, is quoted as a writer who believes in the utility of military force:
““We can lead by the force of high moral example,” he writes, but “fear is much more reliable, and lasts longer. Once we show that we are capable of dealing out terrible punishment to our enemies, our power will be far greater.””
This quotation appeared in an article by Michael Signer, entitled A City on a Hill, which was published in Democracy Journal in Summer 2006 and which was available in May 2014 at http://www.democracyjournal.org/1/6470.php.