Photo: Getty Images

There are 35 Senate seats up for election in 2020 — including a special election in Arizona — many of which are expected to be brutally competitive as Democrats vie for control of the Senate.

Quick take: The Senate is currently made up of 53 Republicans, 45 Democrats and 2 independents who caucus with the Democrats. Dems must win 3 or 4 GOP-held seats to take control of the Senate — 3 if the new vice president is a Democrat and 4 if not.

  • Republican senators representing left-leaning states or states that are shifting demographically — Susan Collins (Maine), Cory Gardner (Colo.) and Martha McSally (Ariz.) — are considered among the Democrats’ clearest 2020 targets.
  • As Democrats from Trump-won states, Sen. Gary Peters (D-Mich.) and Sen. Doug Jones (D-Ala.) are also vulnerable.

Republicans - Cook Political Report race classification:

  • Sen. Martha McSally (Ariz.) - Lean Democratic
  • Sen. Thom Tillis (N.C.) - Toss up
  • Sen. Susan Collins (Maine) - Toss up
  • Sen. Steve Daines (Mt.) - Toss up
  • Sen. Joni Ernst (Iowa) - Toss up
  • Sen. Cory Gardner (Colo.) - Toss up
  • Sen. David Perdue (Ga.) - Toss up
  • Sen. Lindsey Graham (S.C.) - Lean Republican
  • Sen. Kelly Loeffler (Ga.) — Lean R
  • Sen. James Risch (Idaho) - Lean R
  • Open Kansas seat held by retiring Pat Roberts - Lean R
  • Sen. Dan Sullivan (Alaska) - Likely R
  • Sen. John Cornyn (Texas) - Likely R
  • Sen. Mitch McConnell (Ky.) - Solid R
  • Sen. Mike Rounds (S. D.) - Solid R
  • Sen. Ben Sasse (Neb.) - Solid R
  • Sen. Bill Cassidy (La.) - Solid R
  • Sen. Cindy Hyde-Smith (Miss.) - Solid R
  • Sen. James Inhofe (Okla.) - Solid R
  • Sen. Tom Cotton (Ark.) - Solid R
  • Sen. Shelley Moore Capito (W.V.) - Solid R
  • Open Tennessee seat held by retiring Lamar Alexander - Solid R
  • Open Wyoming seat held by retiring Mike Enzi - Solid R

Democrats - Cook Political Report race classification:

  • Sen. Doug Jones (Ala.) - Lean Republican
  • Sen. Gary Peters (Mich.) - Lean Democrat
  • Sen. Cory Booker (N.J.) - Solid D
  • Sen. Chris Coons (Del.) - Solid D
  • Sen. Dick Durbin (Ill.) - Solid D
  • Sen. Ed Markey (Mass.) - Solid D
  • Sen. Jeff Merkley (Ore.) - Solid D
  • Sen. Jack Reed (R.I.) - Solid D
  • Sen. Jeanne Shaheen (N.H.) - Solid D
  • Sen. Tina Smith (Minn.) - Solid D
  • Sen. Mark Warner (Va.) - Solid D
  • Open New Mexico seat held by retiring Tom Udall - Solid D

Editor's note: This story has been corrected to show 35 Senate seats up for election in 2020, not 36.

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