When distrust exists between governments, when there is a danger of war, they will not be willing to disarm even when logic indicates that disarmament would not affect military security at all.
So long as peace is not attained by law (so argue the advocates of armaments) the military protection of a country must not be undermined, and until such is the case disarmament is impossible.
Thus, if armaments were curtailed without a secure peace and all countries disarmed proportionately, military security would have been in no way affected.
One can take exception to this idea on the grounds that a method of disarmament exists which does not interfere with military security.