Were General McClellan's Report nothing more than a report, were the General himself nothing more than an officer endeavoring to palliate a failure, we should not have felt called on to notice his plea, unless to add publicity to any new facts he might be able to bring forward. But the Report is a political manifesto, and not only that, but an attack on the administration which appointed him to the command, supported him with all its resources, and whose only fault it was not sooner to discover his incapacity to conduct aggressive movements. General McClellan is a candidate for the Presidency, and as he has had no opportunity to show his capacity in any civil function, his claim must rest on one of two grounds,--either the ability he has shown as a general, or the specific principles of policy he is supposed to represent. Whatever may be the success of our operations in the field, our Chief Magistracy for the next four years will demand a person of great experience and ability. Questions cannot fail to arise taxing prudence of the longest forecast and decision of the firmest quality. How far is General McClellan likely to fulfill these conditions? What are the qualities of mind of which both his career and his Report give the most irrefragable evidence? General McClellan's mind seems to be equally incapable of appreciating the value of time as the material of action, and its power in changing the relations of facts, and thus modifying the basis of opinion. He is a good maker of almanacs, but no good judge of the weather. Judging by the political counsel which he more than once felt called upon to offer the President, and which, as he has included it in his Report, we must presume to represent his present opinions, he does not seem even yet to appreciate the fact that this is not a war between two nations, but an attempt at revolution within ourselves, which can be adequately met only by revolutionary measures. And yet, if he were at this moment elevated to the conduct of our affairs, he would find himself controlled by the same necessities which have guided Mr. Lincoln, and must either adopt his measures, or submit to a peace dictated by the South. No side issue as to how the war shall be conducted is any longer possible. The naked question is one of war or submission, for compromise means surrender; and if the choice be war, we cannot afford to give the enemy fifty in the game, by standing upon scruples which he would be the last to appreciate or to act upon. It is one of the most terrible features of war that it must be inexorable by its very nature.