Alliances in which each contracting party has different interests will never hold good under all conditions, and therefore cannot represent a permanent political system. "There is no alliance or agreement in the world that can be regarded as effective if it is not fastened by the bond of the common and reciprocal interests; if in any treaty the advantage is all on one side and the other gets nothing, this disproportion destroys the obligation." These are the words of Frederick the Great, our foremost political teacher _pace_ Bismarck. We must not be blinded in politics by personal wishes and hopes, but must look things calmly in the face, and try to forecast the probable attitude of the other States by reference to their own interests. Bismarck tells us that "Illusions are the greatest danger to the diplomatist. He must take for granted that the other, like himself, seeks nothing but his own advantage." It will prove waste labour to attempt to force a great State by diplomatic arrangements to actions or an attitude which oppose its real interests. When a crisis arises, the weight of these interests will irresistibly turn the scale. When Napoleon III. planned war against Prussia, he tried to effect an alliance with Austria and Italy, and Archduke Albert was actually in Paris to conclude the military negotiations.[B] These probably were going on, as the French General Lebrun was in Vienna on the same errand. Both countries left France in the lurch so soon as the first Prussian flag flew victoriously on the heights of the Geisberg. A statesman less biassed than Napoleon would have foreseen this, since neither Austria nor Italy had sufficient interests at stake to meddle in such a war under unfavourable conditions. [Footnote B: When Colonel Stoffel, the well-known French Military Attaché in Berlin, returned to Paris, and was received by the Emperor, and pointed out the danger of the position and the probable perfection of Prussia's war preparations, the Emperor declared that he was better informed. He proceeded to take from his desk a memoir on the conditions of the Prussian army apparently sent to him by Archduke Albert, which came to quite different conclusions. The Emperor had made the facts therein stated the basis of his political and military calculations. (Communications of Colonel Stoffel to the former Minister of War, v. Verdy, who put them at the service of the author.)]