2020 Senate map

Democratic-held

Uncalled

Republican-held

Not in play

NH

ME

MT

OR

MN

ID

SD

MA

WY

MI

RI

IA

NE

NJ

IL

DE

CO

WV

VA

KS

KY

NC

TN

AZ

OK

AR

NM

SC

GA

AL

MS

LA

TX

AK

Special election

for McCain’s seat

Runoff needed

in December 2018

50

21

12

35 Dems. not in play

31 Reps. not in play

2020 Senate map

Democratic-held

Uncalled

Republican-held

Not in play

NH

ME

MT

OR

MN

MA

ID

SD

RI

WY

MI

IA

Special election

for McCain’s

seat

NJ

NE

IL

DE

CO

WV

VA

KS

KY

NC

TN

AZ

OK

AR

NM

SC

GA

AL

MS

LA

TX

AK

Runoff needed

in December 2018

50

35 Dems. not in play

21

31 Reps. not in play

12

35 Dems. not in play

12

19

33 Reps. not in play

2020 Senate map

Democratic-held

Republican-held

Not in play

Uncalled

NH

ME

MT

OR

MN

MA

ID

SD

RI

WY

MI

Special election

for McCain’s

seat

IA

NJ

NE

IL

DE

CO

WV

VA

KS

KY

NC

TN

AZ

OK

AR

NM

SC

GA

AL

MS

LA

TX

AK

Runoff needed

in December 2018

50

35 Dems. not in play

21

31 Reps. not in play

12

2020 Senate map

Democratic-held

Republican-held

Uncalled

Not in play

NH

ME

MT

OR

MN

MA

ID

SD

RI

WY

MI

IA

NJ

NE

IL

DE

WV

Special election

for McCain’s seat

CO

VA

KS

KY

NC

TN

AZ

OK

AR

NM

SC

GA

AL

MS

LA

TX

AK

Runoff needed

in December 2018

50

35 Dems. not in play

21

31 Reps. not in play

12

There’s still one race left in the 2018 election — a special election runoff in Mississippi — but we already know Republicans have expanded their majority. And that’s in large part because it was such a difficult map for Democrats. They had many more seats in play (26) than Republicans (9), and some of those elections took place in deep-red states like West Virginia, Montana, Indiana, North Dakota and Missouri.

So how is the Senate map in 2020? Better for Democrats but still not great.

What have we learned from 2018

Unlike a member of the House, who is beholden to a more homogenous and often politically polarized district, senators are supposed to represent their entire state. This would seem to incentivize more moderate ideologies in the upper chamber. But senators are also very polarized, with the most moderate ones being Republicans in blue states and Democrats in red states, and most others aligning with their parties regularly. The most vulnerable ones tend to be the most moderate ones — in part because their voting records reflect the difficulty of their state.

This chart shows dots for senators in the outgoing Congress positioned horizontally according to their states’ presidential voting records, from most Democratic (⬅) on the left to most Republican on the right (➡) .

Vertically, senators are positioned according to ideology, using a score called DW-Nominate. Conservative senators (⬆) are at the top, and the most liberal (⬇) are on the bottom. Some senators are mismatched, voting out of step with their states’ preferences.

Democrats were defending 26 seats, including several vulnerable seats in states that voted heavily for President Trump in 2016.

Democrats lost about half of the vulnerable seats, with incumbents losing in Florida, Indiana, Missouri and North Dakota. Democrats picked up a vulnerable Republican seat in Nevada, and a narrow win in Arizona provided another flip in a state that Democrats would like to keep competitive. Joe Manchin (D-W.Va.), the most mismatched senator compared to how his state voted for president in 2016, managed to hold on to his seat.

Outlined circles indicate flipped seats

We see a somewhat different picture if we look at senators up for reelection in 2020. This time it’s the Republicans’ turn to defend more seats, but they’re doing so on friendly ground in states that voted heavily for Trump in 2016. So they’re still up for grabs, but many will be hard to flip for Democrats.

There are still a few opportunities for pickups by the Democrats, with both Sens. Susan Collins of Maine and Cory Gardner of Colorado up for reelection in states that voted for Clinton in 2016. After a few Iowa House districts flipped to the Democrats in 2018, Joni Ernst’s seat seems like a potential target as well. They’ll also try to win in blue-trending North Carolina and pick off Arizona’s other Senate seat.

Republicans will have some opportunities, too. Doug Jones of Alabama is the most vulnerable incumbent, as a Democratic senator in a deeply red state. New Hampshire, Minnesota and Virginia will be tough but winnable races if 2020 is a good year for the GOP.

Once again, winning the Senate looks to be a tough slog for Democrats — and that may not change anytime soon. While the House was gerrymandered by Republicans to be more favorable to them, the Senate map is also very tough for Democrats — albeit for different reasons. Democrats simply have more voters clustered in fewer states. So blue California has about 70 times as many people as red Wyoming but the same number of senators. In the 2016 election, President Trump won 30 states, while Hillary Clinton won just 20. That means 60 senators serve in Trump states, while 40 serve in Clinton states.

The urban-rural divide has accentuated this trend. Blue voters are concentrated in urban areas, and big urban areas are concentrated in just a few states. New Jersey has a population of 9 million, according to the U.S. Census Bureau — more than Wyoming, North Dakota, South Dakota, Idaho, Utah and Nebraska together (8.9 million).

Red is

built-up areas

N.D.

OR

S.D.

Idaho

Wyo.

Neb.

AK

200 MILES

Utah

N.J.

Red is built-up

areas

N.D.

OR

S.D.

Idaho

Wyo.

Neb.

AK

200 MILES

Utah

N.J.

NORTH DAKOTA

Red is built-up areas

SOUTH DAKOTA

IDAHO

WYOMING

NEBRASKA

100 MILES

UTAH

N.J.

NORTH DAKOTA

Red is built-up areas

SOUTH DAKOTA

IDAHO

WYOMING

NEBRASKA

100 MILES

UTAH

N.J.

How upcoming Senate maps compare to the 2016 presidential vote

Looking at how each state voted in 2016 has become a key proxy for considering the political lean of each state. This will be particularly important in 2020, with the increased turnout and attention a presidential race provides.

Clinton

Trump

+20%

10

5

2.5

0

2.5

5

10

+20%

ME

WI

VT

NH

AK

ID

WA

MT

ND

MN

IL

MI

NY

MA

OR

NV

WY

SD

IA

IN

OH

PA

NJ

CT

RI

CA

UT

CO

NE

MO

KY

WV

VA

MD

DE

AZ

NM

KS

AR

TN

NC

SC

LA

MS

AL

GA

HI

OK

TX

FL

Seats in play, by current incumbent

Democrat

Republican

Undecided

Independent elected officials that caucus with

the Democratic party are counted as Democrats.

2020

ME

NH

AK

ID

MT

MN

IL

MI

MA

OR

WY

SD

IA

NJ

RI

CO

NE

KY

WV

DE

VA

AZ

NM

NC

KS

AR

TN

SC

LA

MS

AL

GA

OK

TX

2022

WI

VT

NH

AK

ID

WA

ND

IL

NY

OR

NV

SD

IA

IN

OH

PA

CT

CA

UT

CO

MO

KY

MD

AZ

KS

AR

NC

SC

LA

AL

GA

HI

OK

Special

election

in 2020

FL

2024

ME

WI

VT

WA

MT

ND

MN

MI

NY

MA

NV

WY

IN

OH

PA

NJ

CT

RI

CA

UT

NE

MO

WV

VA

MD

DE

AZ

NM

TN

MS

HI

TX

FL

Clinton

Trump

+20%

10

5

2.5

0

2.5

5

10

+20%

ME

WI

VT

NH

AK

ID

WA

MT

ND

MN

IL

MI

NY

MA

OR

NV

WY

SD

IA

IN

OH

PA

NJ

CT

RI

CA

UT

CO

NE

MO

KY

WV

VA

MD

DE

AZ

NM

KS

AR

TN

NC

SC

LA

MS

AL

GA

HI

OK

TX

FL

Seats in play, by current incumbent

Independent elected officials that caucus with

the Democratic party are counted as Democrats.

Democrat

Republican

Undecided

2020

ME

NH

AK

ID

MT

MN

IL

MI

MA

OR

WY

SD

IA

NJ

RI

CO

NE

KY

WV

DE

VA

AZ

NM

KS

AR

TN

IA

SC

LA

MS

AL

GA

OK

TX

2022

WI

VT

NH

AK

ID

WA

ND

IL

NY

OR

NV

SD

IA

IN

OH

PA

CT

CA

UT

CO

MO

KY

MD

AZ

KS

AR

NC

SC

LA

AL

GA

HI

OK

Special

election

in 2020

FL

2024

ME

WI

VT

WA

MT

ND

MN

MI

NY

MA

NV

WY

IN

OH

PA

NJ

CT

RI

CA

UT

NE

MO

WV

VA

MD

DE

AZ

NM

TN

MS

HI

TX

FL

Clinton

Trump

+20%

10

5

2.5

0

2.5

5

10

+20%

ME

WI

VT

NH

AK

ID

WA

MT

ND

MN

IL

MI

NY

MA

OR

NV

WY

SD

IA

IN

OH

PA

NJ

CT

RI

CA

UT

CO

NE

MO

KY

WV

VA

MD

DE

AZ

NM

KS

AR

TN

NC

SC

LA

MS

AL

GA

HI

OK

TX

FL

Seats in play, by current incumbent

Democrat

Republican

Undecided

Independent elected officials that caucus with

the Democratic party are counted as Democrats.

2020

ME

NH

AK

ID

MT

MN

IL

MI

MA

OR

WY

SD

IA

NJ

RI

CO

NE

KY

WV

VA

DE

NC

AZ

NM

KS

AR

TN

SC

LA

MS

AL

GA

OK

TX

2022

WI

VT

NH

AK

ID

WA

ND

IL

NY

OR

NV

SD

IA

IN

OH

PA

CT

CA

UT

CO

MO

KY

MD

AZ

KS

AR

NC

SC

LA

AL

GA

HI

OK

Special

election

in 2020

FL

2024

ME

WI

VT

WA

MT

ND

MN

MI

NY

MA

NV

WY

IN

OH

PA

NJ

CT

RI

CA

UT

NE

MO

WV

VA

MD

DE

AZ

NM

TN

MS

HI

TX

FL

Clinton

Trump

ME

+20%

10

5

2.5

0

2.5

5

10

+20%

WI

VT

NH

AK

ID

WA

MT

ND

MN

IL

MI

NY

MA

OR

NV

WY

SD

IA

IN

OH

PA

NJ

CT

RI

CA

UT

CO

NE

MO

KY

WV

VA

MD

DE

AZ

NM

KS

AR

TN

NC

SC

LA

MS

AL

GA

HI

OK

TX

FL

Seats in play, by current incumbent

Democrat

Republican

Undecided

2020

2022

2024

ME

ME

NH

WI

VT

NH

WI

VT

AK

AK

ID

ID

MT

MN

IL

MI

MA

WA

ND

IL

NY

WA

MT

ND

MN

MI

NY

MA

OR

OR

WY

SD

IA

NJ

RI

NV

SD

IA

IN

OH

PA

CT

NV

WY

IN

OH

PA

NJ

CT

RI

CO

NE

KY

WV

VA

DE

CA

UT

CO

MO

KY

MD

CA

UT

NE

MO

WV

VA

MD

DE

AZ

NM

AZ

AZ

NM

NC

KS

AR

TN

SC

KS

AR

NC

SC

TN

LA

MS

AL

GA

LA

AL

GA

MS

OK

HI

OK

HI

TX

TX

FL

FL

Special

election

in 2020

Independent elected officials that caucus with the Democratic party are counted as Democrats.

Clinton

Trump

ME

+20%

10

5

2.5

0

2.5

5

10

+20%

WI

VT

NH

AK

ID

WA

MT

ND

MN

IL

MI

NY

MA

OR

NV

WY

SD

IA

IN

OH

PA

NJ

CT

RI

CA

UT

CO

NE

MO

KY

WV

VA

MD

DE

AZ

NM

KS

AR

TN

NC

SC

LA

MS

AL

GA

HI

OK

TX

FL

Seats in play, by current incumbent

Democrat

Republican

Undecided

2020

2022

2024

ME

ME

NH

WI

VT

NH

WI

VT

AK

AK

ID

ID

MT

MN

IL

MI

MA

WA

ND

IL

NY

WA

MT

ND

MN

MI

NY

MA

OR

OR

WY

SD

IA

NJ

RI

NV

SD

IA

IN

OH

PA

CT

NV

WY

IN

OH

PA

NJ

CT

RI

CO

NE

KY

WV

VA

DE

CA

UT

CO

MO

KY

MD

CA

UT

NE

MO

WV

VA

MD

DE

AZ

NM

AZ

AZ

NM

KS

AR

TN

NC

SC

KS

AR

NC

SC

TN

LA

MS

AL

GA

LA

AL

GA

MS

OK

HI

OK

HI

Special

election

in 2020

TX

TX

FL

FL

Independent elected officials that caucus with the Democratic party are counted as Democrats.

Laris Karklis contributed to this report.

About this story

The Cook Political Report’s Partisan Voter Index measures partisan lean. To get a score, the 2012 and 2016 presidential election results in each state or congressional district were compared to the national average. Read more.

The first dimension of the DW-Nominate index scores a lawmaker's voting record between -1 (most liberal) and 1 (most conservative). Read more.

Population data from the U.S. Census Bureau.

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