Bismarck was very strongly pressed by the National Liberals to hasten the union with the south; at the beginning of 1870 the Grand Duke of Baden, himself a son-in-law of the King of Prussia and always the chief supporter of Prussian influence in the south, formally applied to be admitted into the Federation.

The request had to be refused, but Bismarck had some difficulty in defending his position against his enthusiastic friends.

He had to warn them not to hurry; they must not press the development too quickly.

If they did so, they would stir the resentment of the anti-Prussian party; they would play into the hands of Napoleon and Austria.

But if there was danger in haste, there was equal danger in delay; the prestige of Prussia would suffer.
It is clear that there was one way in which the union might be brought about almost without resistance, and that was, if France were to make an unprovoked attack upon Germany, an attack so completely without reason and excuse that the strong national passion it provoked might in the enthusiasm of war sweep away all minor differences and party feelings.
There was another element which we must not omit.