I'm surprised that this hasn't gone to the high court sooner. Many will remember the NCAA's attempt to crack down on possibly offensive Native American mascots during the 2004-2005 athletic year by banning offending schools from championships (I believe). The NCAA targeted everyone, even if the teams used accurate tribal names as an homage to local tribes -- like Utes, Seminoles, and the Illini.
Redskins has always been like a circa-1940 racist characture from Cowboy and Indian folklore. For it to last unchallenged in the enlightened politically correct east coast is astounding.
My prediction -- Washington Redskins will become the Washington Red Storm in the 2011-2012 season. However, the conservative majority on the court may hold for the NFL team.