As Sen. Ben Nelson prepares to campaign for re-election, he is doing so in a region that is trending away from him. In 2004, the Great Plains was a power center. Now, it is tilting toward the GOP. (Associated Press)

As Sen. Ben Nelson prepares to campaign for re-election, he is doing so in a region that is trending away from him. In 2004, the Great Plains was a power center. Now, it is tilting toward the GOP. (Associated Press)