Compare how Italy and Germany used realpolitik and war, rather than idealism alone, to achieve national unification between 1859 and 1871.
Italy in the mid-1800s was a patchwork of separate states -- the Kingdom of Sardinia-Piedmont in the northwest, Austrian-controlled territory in the northeast, the Papal States in the center, and the Kingdom of the Two Sicilies in the south. The idealist Giuseppe Mazzini had dreamed of a unified, republican Italy since the 1830s, but it was Camillo di Cavour, the pragmatic prime minister of Piedmont-Sardinia, who actually delivered unification -- not through idealism but through realpolitik, hard-nosed politics based on practical advantage rather than principle. Cavour allied with France in 1859 to defeat Austria and gain Lombardy, while the revolutionary Giuseppe Garibaldi led a volunteer army of "Red Shirts" to conquer Sicily and Naples in 1860 -- then handed his conquests over to Piedmont's King Victor Emmanuel II rather than keep power himself. The Kingdom of Italy was proclaimed in 1861, and Rome, the last holdout, was added in 1870, completing unification.
Germany followed a strikingly similar pattern under Otto von Bismarck, Prussia's chancellor from 1862, who famously declared that the great questions of the age would be decided "not by speeches and majority votes...but by iron and blood." Bismarck engineered three deliberate wars to unify the German states under Prussian leadership: a war against Denmark (1864) over disputed territories, a war against Austria (1866) that excluded Austria from German affairs for good, and a war against France (1870-1871), provoked partly through a leaked, edited diplomatic telegram, that ended in a decisive Prussian victory. On January 18, 1871, German princes proclaimed the new German Empire in the Hall of Mirrors at the Palace of Versailles -- a deliberately humiliating location, chosen inside the defeated enemy's own palace. France was forced to give up the border region of Alsace-Lorraine, a loss that stung for decades and would resurface as a cause of tension leading toward World War I.
Mastery looks like: They can compare Italian and German unification on method, key dates, and outcome, and explain why Bismarck's choice of Versailles for the 1871 proclamation was deliberately significant.
Common stumbles: Flattening both unifications into "some wars happened and then there were two new countries," instead of naming the specific leaders, wars, and dates that explain how and why each succeeded.