PRINCETON, NJ -- The last CNN/USA Today/Gallup survey before Tuesday's congressional elections shows a decided shift in sentiment among likely voters toward Republicans, suggesting the GOP is likely to retain majority control of the U.S. House of Representatives. Two weeks ago, Democrats led among likely voters by three points, 49% to 46%, but the latest poll shows Republicans leading by six points, 51% to 45% -- a nine-point swing in the lead.