tering his basic plan. However, if the
commander takes action along correct lines in due time, he can still
preserve the integrity of his basic plan and so continue to control
the shaping of the situation.

Having re-examined his solution of his basic problem and found it
sound, the commander finds himself under the necessity of resolving a
perplexity as to what to do about the enemy reinforcement. In this
case, he concludes that his proper action is to prevent the enemy
reinforcement from protecting the convoy. This task, self-assigned
because of the demands of the situation, becomes the basis for the
mission of his new problem, the mission being:--

(Task) To prevent the enemy reinforcements from protecting the
convoy,

(Purpose) in order to contribute to the eventual destruction
of the convoy.

The commander now considers the various courses of action open to him
for the accomplishment of this mission. He also considers the enemy
courses of action. He then considers each of the former in relation to
each of the latter. He compares, on this basis, each of his retained
courses of action with the others and so selects the best course of
action. Finally, he arrives, in this manner, by the same process as in
a basic problem (Chapter VI), at a decision as to the best course of
action. Should this decision be to sink the enemy reinforcement, its
statement linked to its purpose, would be:--

To destroy the enemy reinforcement, in order to prevent it
from protecting the convoy.

Problems Challenging the Integrity of the Basic Plan

During the planned action, a change in the situation may have the
effect of challenging the integrity of the basic plan. The commander
is then faced by a problem calling for the exercise of the highest
order of ability. While problems of this type probably occur with
least frequency, they are the most important of those which may be
encountered during the fourth step.

Because such a problem, arising from the demands of a new situation,
requires a re-estimate of the basic situation, the essential procedure
is the same as for a basic problem (Chapter VI), but certain
modifications necessarily appear.

Summary of the Situation. While a commander will rarely find himself
operating without instructions, the importance of problems arising
when no directive applies is not lessened by the fact that such
problems may infrequently occur. When the commander is faced with