The GOP recently conducted a poll in which they asked Republicans, Democrats, and Independents to indicate their level of approval/disapproval of various GOP and Dem messages on topics like Iraq, the economy, trade, and taxes.  The results are summarized here.  The GOP messages did worse on all issues when people were not told that it was a GOP message than when the GOP brand was attached.  Presumably pollsters are telling GOP candidates that identity politics and the politics of personal destruction are both more effective for them than either brand or message.