George F. Will’s statement [“Ukraine: A crisis that matters,” op-ed, Feb. 20] that “nationalism is a necessary, although insufficient impulse sustaining liberty” needs clarifying. Nationalism must be distinguished from patriotism.

Patriotism is fundamental to liberty because pride in one’s nation-state, and a willingness to defend it if necessary, is the basis of national independence. Patriotism is the courage of national self-determination.

By contrast, nationalism is patriotism transformed into a sentiment of superiority and aggression toward other countries. Nationalism is the poisonous idea that one’s country is superior to somebody else’s. Nationalism is intrinsically a cause of war and imperialism.

In the Ukraine conflict, Russian President Vladimir Putin is a nationalist imperialist and the Kiev protesters are patriots.

Ronald Tiersky, Amherst, Mass.