Facing an energized Republican Party and deep-pocketed conservative groups, President Obama is kicking off his 2012 reelection campaign with a concerted push for help from wealthy donors and liberal groups unbound by spending limits.
33 out of 100 seats are up for election. 51 are needed for a majority.
|Seats gained or lost||+2||-2|
* Includes two independent senators expected to caucus with the Democrats: Angus King (Maine) and Sen. Bernie Sanders (Vt.).
All 435 seats are up for election. 218 are needed for a majority.