Leopold II. was one of the shrewdest and most cautious of men. He knew how to wait, and how to give way. He had no wish that his brother-in-law should again be powerful, and he was not sorry that France should be disabled by civil dissension. But he could not abandon his sister without dishonour; and he was afraid of the contagion of French principles in Belgium, which he had reconciled and pacified with difficulty. Moreover, a common action in French affairs, action which might eventually be warlike, was a means of closing the long enmity with Prussia, and obtaining a substitute for the family alliance with France, which had become futile. Therefore he was prepared, if they had escaped, to risk war for their restoration, and induced the Prussian agent to sign an undertaking which went beyond his instructions.
When the disastrous news reached him from Varennes, Leopold appealed to the Powers, drew up an alliance with Prussia, and joined in the declaration of Pilnitz, by which France was threatened with the combined action of all Europe unless the king was restored to a position worthy of kings. The threat implied no danger, because it was made conditional on the unanimity of the Powers. There was one Power that was sure not to consent. England was waiting an opportunity to profit by French troubles. It had already been seriously proposed by Bouillé, with the approval of Lewis, to purchase aid from George III. by the surrender of all the colonies of France. Therefore Leopold thought that he risked nothing by a demonstration which the _émigrés_ made the most of to alarm and irritate the French people. But when the king freely accepted the Constitution, the manifesto of Pilnitz fell to the ground. If he was content with his position, it could not be the duty of the Powers to waste blood and treasure in attempting to alter it. The best thing was that things should settle down in France. Then there would be no excitement spreading to Belgium, and no reason why other princes should be less easily satisfied than Lewis himself. "The king," said Kaunitz, "the king, good man, has helped us out of our difficulty himself." Still more, when he obtained a revival of popularity which seemed a marvel after the events of June, when he freely vetoed acts which he disapproved, and appeared to be acting in full agreement with a powerful and still dominant party, the imperial government hoped that the crisis was over. And this was the state of things in October and November.