After 1848, the conservative side also started encouraging nationalism. Promoting state power and achieving political domination came to represent nationalism. The cases of Germany and Italy provide good evidences in this regard.
Germany
After the monarchies and the military crushed the liberal movements of middle class elites in Germany, Prussia took the leadership of the movement for national unification.
The Chief minister Otto von Bismarck with the help of Army and bureaucracy carried out the process. France, Austria and Denmark fought three wars within 7 years.
In January, 1871, the Prussian King Kaiser Williams I became the German Emperor in the palace of Versailles in the presence of top ministers including Bismarck.
The nation building process in Germany actually reflected the Prussian State Power. The new state placed a strong emphasis on modernizing the currency, banking, legal and judicial systems in Germany.
Kaiser Williams I, German Emperor
Italy
In the mid-nineteenth century, Italy was divided into 7 states, ruled by Italian princes, the Pope, Austrian Habsburg and Bourbon Kings of Spain. There was no unified nation-state and no single sovereign power.
Italian language was not even a common language and several variations existed.
In 1830s, liberal Giuseppe Mazzini argued for a unified Italian republic.
Giuseppe Mazzini formed secret society Young Italy for spreading his idea. But the revolutions of 1830 and 1848 failed in Italy.
The duty to unite Italy fell on King Victor Emmanuel I, ruler of Sardinia-Piedmont, a state in Italy. Sardinia defeated Austrian forces in 1859 under the leadership of the Chief Minister Cavour.
In 1860, they matched into south Italy and defeated kingdom of Sicily. This way, in 1861, Emmanuel II was proclaimed king of united Italy.
Victor Emmanuel I
Unique case of Britain
Britain is the earliest form of Nation-state. However, there was no nation-state in Britain before the eighteenth century.
The region was divided among English, Scottish, Welsh and Irish. But when the English grew more powerful, then it started dominating others.
After glorious revolution of 1688 and setting up of parliament, the nation-state emerged by keeping England at its core.
England and Scotland signed Act of Union in 1707. It created the United Kingdom.
In Ireland, the English supported Protestants against Catholics in the society. The Catholics rebelled back.
But the English crushed the rebellion and forced Ireland to join UK in 1801. This way the British nation as United Kingdom came into existence.