Under these circumstances the commander reviews his estimate in all its aspects. By minute re-examination he endeavors to find ways of accomplishing his assigned task. If he cannot accomplish the task, he seeks for ways whereby he can further such accomplishment so far as is reasonably feasible. If unable, in any degree, to further the accomplishment of his task, he endeavors to contribute, so far as he feasibly and acceptably can, to the accomplishment of the purpose of his mission. It is to be expected, of course, that, if unable to accomplish his assigned task, the commander will make constructive representations (page 103) to higher authority. The latter may then assign additional forces or may otherwise alter the problem,--for example, by assigning a new task. However, a situation such as described may occur when the commander is alone in a distant theater or when for other reasons he finds himself unable to communicate, in time, with higher authority. In such a situation the commander is under the necessity of determining, for himself, a task which is suitable, feasible, and acceptable under the circumstances (page 52). It is evident that, at some point in the foregoing procedure, the commander has been forced to abandon the solution of his basic problem, because he has found that there is no sound solution. He has not completely abandoned the solution of his original problem, because he has not yet exhausted all of its possibilities. However, the solution of the original problem has unquestionably entered a new phase, or step. The new step presents the commander with a new problem, a phase in the solution of the original problem; the new problem is related to the abandoned basic problem, because it arises out of the same situation, which has not changed. The new problem is, however, differentiated from the basic problem because it is based on a different incentive. The incentive for the solution of the new problem arises directly out of a decision made by the commander himself, i.e., his decision that no sound solution for the basic problem can be found. The new problem is one for the commander himself to solve, i.e., it cannot properly be delegated to a subordinate for solution, because its solution is necessary as a basis for the commander's detailed plan. For these reasons the new problem is, by definition (page 106), a subsidiary problem, of the type distinctive of the second step. At what point in the solution of the original problem does the commander abandon the basic problem and proceed with the solution of the new, subsidiary problem which has arisen as described? There are various possible answers, all with a basis of reason, to this question.