Third in order is the factor of diplomacy. Diplomacy here has a two-fold task to perform. First, it must bring about war at the moment most favorable for its own country from the international as well as the military standpoint. Second, it must employ methods which throw the burden of responsibility for the bloody conflict, in public opinion, on the enemy government. The exposure of diplomatic trickery, cheating and knavery is one of the most important functions of Socialist political agitation. But no matter to what extent we succeed in this at the crucial juncture, it is clear that the net of diplomatic intrigues in themselves signifies nothing either as regards the historic rôle of the war or its real initiators. Bismarck’s clever manoeuvres forced Napoleon III to declare war on Prussia, although the actual initiative came from the German side. Next follows the purely military aspect. The _strategic_ plan of operations can be calculated chiefly for defense or attack, regardless of which side declared the war and under what conditions. Finally, the first tactics followed in the carrying out of the strategic plan not infrequently plays a great part in estimating the war as a war of defense or of aggression. "It is a good thing," wrote Engels to Marx on July 31, 1870, "that the French attacked first on German soil. If the Germans repel the invasion and follow it up by invading French territory, then it will certainly not produce the same impression as if the Germans had marched into France without a previous invasion. In this way the war remains, on the French side, more Bonapartistic." Thus we see by the classic example of the Franco-Prussian War that the standards for judging whether a war is defensive or aggressive are full of contradictions when two nations clash. Then how much more so are they when it is a clash of several nations. If we unroll the tangle from the beginning, we arrive at the following connection between the elements of attack and defense. The first _tactical_ move of the French should--at least in Engels’ opinion--make the people feel that the responsibility of attack rested with the French. And yet the entire _strategic_ plan of the Germans had an absolutely aggressive character. The _diplomatic_ moves of Bismarck forced Bonaparte to declare war against his will and thus appear as the disturber of the peace of Europe, while the military-political initiative in the war came from the Prussian government. These circumstances are by no means of slight importance for the _historical_ estimate of the war, but they are not at all exhaustive. One of the causes of this war was the growing ambition of the Germans for national self-determination, which conflicted with the dynastic pretensions of the French Monarchy. But this national "war of defense" led to the annexation of Alsace-Lorraine and so in its second stage turned into a dynastic war of conquest.