Two realities have increasingly become clear as this year's midterm Senate campaigns have taken shape. One is that enough seats are in play to give Republicans, who didn't even have the numbers to mount a filibuster on their own a year ago, a Senate majority. The other is that the Tea Party movement -- which essentially represents the disgruntled base of the GOP -- has forced enough fringe candidates on the party in enough marginal races to jeopardize the GOP's chances of fully capitalizing on what is a very favorable political climate.