In some instances war has increased American consciousness about the nation's ideals and identity, and the public's awareness of its failings to live up to the principles it professes. The War for Independence, for example, made plain the contradiction between the practice of slavery and struggle for liberty. Although independence resulted in the abolition of slavery in the North, the institution continued in half the nation after that war and racism existed in all sections of the country. One of the ironies of American history is that gains made by blacks in the Revolutionary War were lost by a later generation. One of the tragedies of that same history is that the Civil War, which fundamentally altered American society and culture by ending slavery, did not destroy the underlying racism that would produce more than a century of segregation following that war.

Racial segregation...