Estimate of One's Own Capacity.
Naturally, no sane Theater commander would rely on psychological warfare alone for the accomplishment of a military result. It is possible, nevertheless, to allow for planned good luck—good luck which one has created with many months of hard work. When psychological warfare is used in conjunction with invasion, its planned use (to judge by the results found in World War II) might often justify commanders in using minimum rather than maximum allocations of troops for the protection of lines of communications against guerrilla or civilian attack. If the Nazis had chased the Soviet peasants through the woods with soup kitchens, free movies, and mittens for the babies, they would not have had so many furious partisans sniping at them.
Psychological warfare can be relied upon to a considerable degree to step up enemy panic in the application of a rapid forward movement. The Japanese in China panicked whole regiments of local volunteers plumb out of existence by the use of fast-marching Chinese-speaking plainclothes troops, some of whom may have been air-dropped. In the Nazi establishment of the first salient through to Abbeville, the psychological aspects of the blitzkrieg helped prevent the British and French from re-forming a continuous line and led eventually to the pocketing of the British at Dunkirk.
Psychological warfare can also be counted on, tactically, to speed up the reduction of isolated enemy positions when these positions are clearly beyond hope of rescue. All the psychological warfare people need to do is to go in with map leaflets, surrender leaflets, loudspeakers and a near-by radio. The unit may not give in instantly, but the unit would be superhuman if it fought as well in the face of persuasion as it would have fought without psychological attack. In the mopping-up of Japanese in the Pacific island fighting, psychological warfare teams and techniques undoubtedly eased and speeded the process.
These references are to tactical estimates. Strategic propaganda is beyond estimate. All it can do is to weight the probabilities a little more favorably than would be the case without it. If the United States had not dropped the Japanese surrender proposal in Japanese all over Japan, the Japanese government leaders might have been more inclined to resist surrendering. If the Germans had not softened up the French before the Great Western Blitz of 1940, they might have needed more time, days or weeks more to reduce France, and thus might have faced a united French overseas Empire even after France-in-Europe fell. The success of a strategic propaganda operation cannot be guaranteed in any plan. It would be foolhardy optimism to think that psychology can assume a major portion of responsibility for direct military results. It would appear that the Soviet Red Army, despite its propaganda-conscious Communist background, never passed the whole buck to psychological warfare. The Russians never appeared to leave the artillery at home in order to take the loudspeakers or leaflet mortars along. They made brilliant, almost terrifying use of pre-belligerent propaganda; they used propaganda tactically with immense success in the taking of prisoners; they used psychological warfare, with a heavy infusion of political warfare, more drastically for consolidation and occupation purposes than did any of the other United Nations. But like everyone else, they seem to have used strategic propaganda for whatever it might bring in—immediate generalized effect, and the ultimate production of windfalls.
Tactical psychological warfare can be estimated, though to a limited extent, as part of a tactical potential of either the enemy or one's own side. Strategic propaganda can be planned and evaluated only in terms of the diffuse general situation, with the reasonable and fair expectation that if properly employed it will better the position of the user. It sometimes achieves results which astound even the originators, but these results cannot be calculated (except by hunch) in advance. Nevertheless, the operation is well worth trying since it has incalculable possibilities and is quite inexpensive in relation to the gross cost of war.