There was opposition among the German speaking regions. The German states reached no agreement on how they should be united. There was even a question that if all German speaking land should united into a nation. The Austrian opposed the plan since this may spread nationalism which may result in the collapse of her multi-national empire. Also, her non-German subjects were a barrier to the road to unification. Prussia and other smaller states did not agree the unity of Germany as the latter was afraid of the loss of powers.
Besides, the opposition of the powers also made the unification of German impossible. Austria strongly opposed to the action of unifying Germany because it was afraid to lose its land to join to form a new Germany. At the same time, Prussia didn’t want to see the unification movement as well because the king preferred to the absolutism than the constitutional government. The weakness of the Prussian Assemblies became an obstacle of the unification of German. In addition, there was no army to support the parliament as well.
France also opposed the idea of unification. France was edger to spread her own influence to some Southern German states, which were jealous of the Austrian supremacy. She intended to have a step on German affairs hoping to make a balance in central Europe. Any unification movement would hinder her French influence development in Germany. She strongly oppose to those attempts to unify Germany which will affect herself.
However,
Firstly, the creation of the Zollverein paved the road to a greater unity economically and later politically. The uniform tariff system promoted trade, communication and economic co-operation among the German states. Prussia benefited form this and she became economically strong. With the closer link in economics affairs, Germans started to think of unification not just in trade but also in politics. And the Prussian leadership in the Zollverein also made the Germans to believe that Germany could be united without Austria but under Prussia.
Secondly, the growth of nationalism pulled the Germans closer. The sense of common nationality kept on growing in German-speaking land with the more and more co-operation between Germans in each state. When the war scare broke out in 1840, all Germans became patriots and treat themselves as a whole. Patriotic songs, flags and poems appeared as a sign of the climax of nationalism.
Thirdly, growing liberalism in some parts of Germany was significant to the greater unity too. In Southern Germany like in Bavaria, Baden and Wurttemburg, constitutions and representative assemblies were granted to Germans. As liberals demanded a united Germany with a constitutional government, therefore the growth of liberalism favoured the growth of a greater unity of Germany.