The cause for this was a double one.

It was partly that Prussia was really not strong enough to meet the coalition of Austria and Russia, but it was also that the King was really of two minds; he was constitutionally unable to maintain against danger a consistent course of policy.
Bismarck was one of the few men who defended the action of the Ministry.
In the ablest of all his speeches he took up the gauntlet, and exposed all the weakness and the dangers of Radowitz's policy.

This was not a cause in which Prussia should risk its existence.

Why should they go to war in order to subject Prussia not to the Princes but to the Chambers of the smaller States?
A war for the Union would, he said, remind him of the Englishman who had a fight with the sentry in order that he might hang himself in the sentry-box, a right which he claimed for himself and every free Briton.

It was the duty of the councillors of the King to warn him from a policy which would bring the State to destruction.
"Still I would not shrink, from the war; I would advise it, were anyone able to prove to me the necessity for it, or to point out a worthy end which could be attained by it and in no other way.
Why do great States wage war nowadays?
The only sound principle of action for a great State is political egoism and not Romanticism, and it is unworthy of a great State to fight for any matter which does not concern its own interests.