On the morning before Election Day, the Rasmussen Reports Senate Balance of Power summary rates 48 seats as Democrat or Leans Democrat, 48 seats as Republican or Leans Republican, and four Toss-Ups that will determine control of the Senate. Today, we are shifting Tennessee from “Leans Republican” to “Toss-Up” and Montana from “Leans Democrat” to “Toss-Up.” They join Missouri and Virginia in the Toss-Up column. See our complete State-by-State Summary.

Rhode Island and Maryland remain in the “Leans Democrat” category.

If all of the races go as expected, Democrats would have to win three of the four remaining Toss-Ups to reach the magic number of 51 seats to gain control of the Senate. If the Democrats win two Toss-Ups, there would be a 50-50 tie. In that circumstance, Vice-President Dick Cheney would cast the deciding vote in his Constitutional role as the presiding officer of the Senate.

Connecticut Senator Joe Lieberman (D) is now running for re-election as a Independent after losing a Primary Campaign to Ned Lamont (D). However, this race has no impact on the Senate Balance of Power considerations since whichever candidate wins will line up as a Democrat when the Senate convenes next January.

History of Changes

On November 4, we switched Tennessee from “Toss-Up” to “Leans Republican.”

On November 3, we switched New Jersey and Montana from “Toss-Up” to “Leans Democrat.” We switched Ohio from “Leans Democrat” to “Democrat.”

On October 30, we shifted Washington from "Leans Democrat" to "Democrat"

On October 20, we shifted the Montana Senate race from "Leans Democrat" to "Toss-Up"

On October 16, we shifted the Virginia Senate race from "Leans Republican" to "Toss-Up"

On October 13, 2006, we shifted the Tennessee Senate race from "Leans Democrat" to "Toss-Up"
On October 10, we shifted the Pennsylvania Senate race from "Leans Democrat" to "Democrat."

On October 9, we shifted Michigan and Minnesota from "Leans Democrat" to "Democrat."

On October 2, we shifted Tennessee from “Toss-Up” to “Leans Democrat.”

On September 25, we shifted Washington from “Democrat” to “Leans Democrat”

On September 18, Montana, Rhode Island, and Ohio all shifted from “Toss-Up” to “Leans Democrat.”

On September 12, Washington shifted from “Leans Democrat” to “Democrat.”

On September 8, Tennessee moved from “Leans Republican” to “Toss-Up.”

On September 6, New Jersey shifted from “Leans Democrat” to “Toss-Up.”

On September 5, Rhode Island moved from “Leans Democrat” to “Toss-Up.”

On the first day of September, Rasmussen Reports changed the Minnesota Senate race from “Democrat” to “Leans Democrat.”

On August 25, we shifted Pennsylvania from “Democrat” to “Leans Democrat.” Santorum remains the nation’s most vulnerable incumbent, but he has closed to within single digits.

On August 24, Washington moved from “Democrat” to “Leans Democrat.”

On August 18, in the wake of controversial remarks by Senator George Allen, Virginia changed from “Republican” to “Leans Republican.