As Doug points out, except when it helps people defend against colonization, nationalism isn't pretty. (Even then, nationalism can be a problem: look at how China and Viet Nam fought. Cambodian nationalism under Pol Pot was worse than disgusting.) That suggests that I need to stress that the period of what I termed "deglobalization" (roughly the 1890s to the 1940s) was hardly pleasant. Contention between nation-states encouraged bloody wars and trade wars. The period when the US was able to enjoy autocentric growth the most (roughly 1945-70) was also a period of colonial wars (against Viet Nam), McCarthyism, and militarism, while women and minorities were largely excluded from the benefits of the "golden age." The advantage of deglobalized, autocentric, growth is that it makes the efforts of the labor movement, the women's movement, civil rights movements, etc., easier. There's a smaller geographical area to fight over. Even then, there's the temptation to "think nationally" rather than globally. -- Jim Devine
