Complex sentence: High intensity warfare helicopter tactics in the West was developed in the context of the Cold War saw the helicopter forces of the Western Allies as being critical in blunting any possible massed attack by overwhelming numbers of Soviet men and armour.
Split into simpler sentences: High intensity warfare helicopter tactics in the West were developed in the context of the Cold War. The helicopter forces of NATO were seen as being critical to blunt any possible massed attack by overwhelming numbers of Soviet soldiers and armour.