Why did Danish leaders expect Prussia to be distracted in 1863?

In 1863, Danish leaders believed that Prussia would be too distracted to intervene effectively in the Schleswig-Holstein question due to its preoccupation with a Polish rebellion against Russia—the January Insurrection—as well as ongoing internal constitutional struggles and a rivalry with Austria for supremacy within the German Confederation.21

Based on this assessment, the Danish government felt emboldened to separate Holstein from the rest of the kingdom and implement a new constitution that effectively annexed Schleswig to Denmark. This move, however, violated previous international agreements, and the Danish expectation of Prussian distraction proved to be a miscalculation. Prussia, under the leadership of Otto von Bismarck, reacted decisively, leading to the German-Danish War in 1864.12