There is slim chance that only one party will be elected to Congress.

All of the House members are up for election every two years. Their terms start in even numbered years, including this one. All 435 are up this year.

The Senators are elected for 6 year terms. About 1/3 of them are up for re-election every 2 years on even numbered years.

http://www.mahoney.house.gov/index.p...temid=99999999

Plus there are always some Independents sprinkled through the mix.
Maybe more Independents need to be elected to Congress to keep an eye on the Dems and the Reps.