In 2008, Barack Obama utilized demographic shifts, his campaign's unprecedented financial resources, and his unique political profile to expand dramatically the electoral map for a Democratic presidential nominee, carrying formerly deep-red states like North Carolina, Indiana and Virginia.
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.