Springsteen wrote a New York Times editorial last week about why musicians speak out. He wrote, “A nation's artists and musicians have a particular place in its social and political life. Over the years I've tried to think long and hard about what it means to be American: about the distinctive identity and position we have in the world, and how that position is best carried. I've tried to write songs that speak to our pride and criticize our failures."

(and so it goes)

The rest of Springsteen's editorial - http://www.nytimes.com/2004/08/05/opinion/05bruce.html