With 258 of the 435 U.S. House seats, Democrats are strongly favored to retain their majority in the 2010 elections -- though history points to party losses in the first midterm election of President Obama.

Most of the 435 congressional districts have such well-entrenched incumbents that the 2010 House races there will be landslides. But CQ Politics has preliminarily identified 99 districts, 67 of which are held by Democrats, where the contests should be highly or mildly competitive. Of these, CQ Politics rates four districts as leaning toward takeover by the challenging party: Louisiana 2, Deleware's at large and Illinois all held by Republicans, and the Democratic-held 3rd District in Louisiana.

See our full chart of all House Races by rating. Learn more about our race rating system.