If she continued to support the Western Powers she would incur the hatred of Russia; then, perhaps, by a sudden change of policy on the part of Napoleon, she would be left helpless and exposed to Russian vengeance.

If war were to break out, and Prussia took part in the war, then the struggle between France and Russia would be fought out on German soil, and, whoever was victorious, Germany would be the loser.

What interests of theirs were at stake that they should incur this danger?
why should Prussia sacrifice herself to preserve English influence in the Mediterranean, or the interests of Austria on the Danube?
He wished for exactly the opposite policy; the embarrassment of Austria must be the opportunity of Prussia; now was the time to recover the lost position in Germany.

The dangerous friendship of Austria and Russia was dissolved; if Prussia came to an understanding with the Czar, it was now Austria that would be isolated.

The other German States would not desire to be dragged into a war to support Austrian dominion in the East.