Having a common enemy unified the American people's diverse ethnic groups before the end of the Cold War.
Anne Quindlin in her commentary for "Newsweek" wrote "A Quilt of a Country" to show how a unified body of America can be had. Though the backgrounds of the many diverse citizens of this great nation may have been from all corners of the world, she asserts that unity is achieved whenever there is a common enemy.
Whether it be the Cold War or the 9/11 attacks, the American people always stay united for defending their nation. There may be instances of one group of people attacking another, or killing or any prejudice, but when the nation is faced with it's own 'outside' enemy, then these differences are set aside and forgotten. America may be the melting pot of numerous cultures and nationalities, but that has never stopped anyone from fighting together against the common enemy.