Clausewitz, perhaps to a greater degree than any other writer, captures the unchanging elements of war. His accomplishments notwithstanding, there nonetheless are many reasons to take care interpreting Clausewitz. First, his observations are incomplete and, at times, ambiguous and contradictory. Second, his writing tends toward the metaphysical and is steeped in early 19th-century German philosophy. Third, some of On War has been overtaken by events, such as the rise of air power and the advent of nuclear weapons, and parts are therefore outdated. It also ignores relationships between land and sea power. Finally, some professed disciples of Clausewitz, such as Lenin, Trotsky, and the Prussian General Staff, have tainted On War with sinister connotations.
Despite these problems, however, so much of On War seems as timely today as when it was first written. The challenge is to use his ideas as a guide, not a blueprint, so as to constantly strive for the versatile, efficient, and effective armed forces that can win their assigned battles, without losing sight of the political purpose for which they are being waged.