Generally, implanting the belief in people that they constitute a nation, and behave in accord with this; for example, defence of sovereignty or revolution to attain self-determination, or self-governing status. Perception of historic nationhood may be based on homogeneity or continuity of geographical tenure, or claims or history of linguistic or ethnic homogeneity. Claimed uniqueness of religion has also been a factor.
Non-monarchial nationalism rose as a dominant force in the 18th century in Western Europe and in North America and has since penetrated nearly every part of the world. It is closely linked with the development of popular sovereignty in the form of free-market or people's democratic republics; the growth of secularism; the lessening of religious, tribal, clannish, or feudal loyalties; and the spread of urbanization, industrialization, and improved communications. Nationalist movements often rise up in opposition to foreign influences as to the rule of outside colonial powers or in reaction to international trends like industrialization which are observed to be destroying national values.
Unitary nation-states are those allowing little or no autonomy to regions, provinces, cities etc. The most unitary nation-states have one national constitution, one general system of laws, and a centralized apparatus for executive, legislative and judicial functions. The opposite type is the federated nation-state.
Nationalism is an attitude in history that constitutes an immense reservoir of human virtues, which, in the face of foreign threat and domination, can rally the struggle to defend ones' own identity and contribution to the historical process.
(a) Nationalism can become an isolationist factor or an instrument of mystification of the masses; (b) can turn into Statist Fascism or Socialism or despotic regimes; (c) lead to the assumption of national superiority and exclusiveness; (d) lead to war; (e) divert the masses from the real issues of a country; and (f) foment discontent among like people of different countries.