The burden of proof, as always, is with the claimant. There is no
evidence whatsoever that the possession of nuclear weapons ever deterred
anything. That kind of proof --- negative proof --- is probably
impossible to obtain, and statements such as the above are speculation
about causes which cannot be supported. OTOH, there is ample proof that
the existance of nuclear weapons has, on many occasions, brought the
world community to the brink of disaster.
I find the fact that people still regurgitate this rhetoric about the
"logic of nuclear deterrence" absolutely baffling. This viewpoint is
astoundingly anachronistic in this day and age, where most educated
people understand that the existance of these things *period* adds
substantial actuarial risk to prospects for both individual and species
survival, as well as having broad negative impact on our
highly-connected global economic "web."