structural:reformatting, information:highlighting, structural:expansion
Criticism

Critics of nationalism have argued that it is often unclear what constitutes a nation, or whether a nation is a legitimate unit of political rule. Nationalists hold that the boundaries of a nation and a state should coincide with one another, thus nationalism tends to oppose multiculturalism and anti-racism. It can also lead to conflict when more than one national group finds itself claiming rights to a particular territory or seeking to take control of the state.

Philosopher A. C. Grayling describes nations as artificial constructs, "their boundaries drawn in the blood of past wars". He argues that "there is no country on earth which is not home to more than one different but usually coexisting culture. Cultural heritage is not the same thing as national identity".

Nationalism is considered by its critics to be inherently divisive, as adherents may draw upon and highlight perceived differences between people, emphasizing an individual's identification with their own nation. They also consider the idea to be potentially oppressive, because it can submerge individual identity within a national whole and give elites or political leaders potential opportunities to manipulate or control the masses. Much of the early opposition to nationalism was related to its geopolitical ideal of a separate state for every nation. The classic nationalist movements of the 19th century rejected the very existence of the multi-ethnic empires in Europe, contrary to an ideological critique of nationalism which developed into several forms of internationalism and anti-nationalism. The Islamic revival of the 20th century also produced an Islamist critique of the nation-state. (see Pan-Islamism)

At the end of the 19th century, Marxists and other socialists and communists (such as Rosa Luxemburg) produced political analyses that were critical of the nationalist movements then active in Central and Eastern Europe, although a variety of other contemporary socialists and communists, from Vladimir Lenin (a communist) to Józef Piłsudski (a socialist), were more sympathetic to national self-determination.

In his classic essay on the topic, George Orwell distinguishes nationalism from patriotism (which he defines as devotion to a particular place). More abstractly, nationalism is "power-hunger tempered by self-deception". For Orwell, the nationalist is more likely than not dominated by irrational negative impulses:

A nationalist is one who thinks solely, or mainly, in terms of competitive prestige. He may be a positive or a negative nationalist—that is, he may use his mental energy either in boosting or in denigrating—but at any rate his thoughts always turn on victories, defeats, triumphs and humiliations. He sees history, especially contemporary history, as the endless rise and decline of great power units and every event that happens seems to him a demonstration that his own side is on the upgrade and some hated rival is on the downgrade. But finally, it is important not to confuse nationalism with mere worship of success. The nationalist does not go on the principle of simply ganging up with the strongest side. On the contrary, having picked his side, he persuades himself that it is the strongest and is able to stick to his belief even when the facts are overwhelmingly against him.

In the liberal political tradition, there was mostly a negative attitude toward nationalism as a dangerous force and a cause of conflict and war between nation-states. The historian Lord Acton put the case for "nationalism as insanity" in 1862. He argued that nationalism suppresses minorities, places country above moral principles and creates a dangerous individual attachment to the state. He opposed democracy and tried to defend the pope from Italian nationalism. Since the late 20th century, liberals have been increasingly divided, with some philosophers such as Michael Walzer, Isaiah Berlin, Charles Taylor and David Miller emphasizing that a liberal society needs to be based in a stable nation state.

The pacifist critique of nationalism also concentrates on the violence of some nationalist movements, the associated militarism, and on conflicts between nations inspired by jingoism or chauvinism. National symbols and patriotic assertiveness are in some countries discredited by their historical link with past wars, especially in Germany. British pacifist Bertrand Russell criticized nationalism for diminishing the individual's capacity to judge his or her fatherland's foreign policy. Albert Einstein stated that "Nationalism is an infantile disease. It is the measles of mankind". Jiddu Krishnamurti stated that "Nationalism is merely the glorification of tribalism ".

Transhumanists have also expressed their opposition to nationalism, to the extent that some transhumanists believe national identities should be dissolved entirely. The influential transhumanist FM-2030 refused to identify with any nationality, referring to himself as 'universal'. Furthermore, in The Transhumanist Handbook, Kate Levchuk stated that a transhumanist "doesn't believe in nationality".