Unless we were prepared to unleash a full-scale nuclear war as soon as some local incident occurs in some distant country, we must have conventional forces in readiness to deal with such situations as they arise.
—Winston Churchill. Speech to the House of Commons, March 1, 1955.
Nuclear-armed nations must maintain sufficient conventional defensive capability to deter aggression in circumstances where recourse to nuclear weapons would be inappropriate or undesirable. An example would be the position the British found themselves in when the Falkland Islands were invaded. Both the Junta and the Argentine people knew that the British had nuclear submarines armed with nuclear weapons. However, neither the Junta, nor presumably the cheering Argentine crowds, ever considered it a serious possibility that Britain would attack Argentina with nuclear weapons. This is singular because it proves that the aggressors were relying upon British nuclear forbearance. The Junta also calculated that the British, lacking proper aircraft carriers, would be unable to retake the islands. Thus, it can be seen that the parlous condition of British conventional forces encouraged the invasion of the Falklands, while Britain’s ability to deliver nuclear weapons did nothing to deter it.
To have a deterrent effect, conventional forces must be strong and credible. Maintaining ranks of perfectly drilled soldiers with shiny brass buckles is useless unless they possess, and are trained to use, the latest modern weapons. Even moderately outdated armed forces are useless in a fight with an enemy possessing superior technology.