The phrase 'ethnic groupO is now part of daily news and political discourse. More ominously, the term Oethnic cleansingO has entered the language in the aftermath of the collapse of Yugoslavia. Despite phrases such as this, we often think of ethnic difference as benign_whether exemplified in food, dress, or music. But is it? Are the kinds of sentiments that we call ethnic_or national_as potentially destructive as those we call racist? Are marches...