US SEN 2020: Which GOP Senate seats are the most vulnerable?

[I’m not Stu]

GOP Senate seats that have at least a non-zero chance to flip:
Joni Ernst
Thom Tillis
David Perdue (possibly retires)
John Cornyn (possibly retires)
Cory Gardner
Steve Daines (Steve Bullock might run)
Susan Collins (possibly retires)
Shelley Moore Capito (if Jim Justice runs)
Dan Sullivan
Pat Roberts (likely retires)

[Kamala]

In my dream, Jason Frerichs wins the 2018 open House seat in South Dakota and then turns it around and unseats Rounds in 2020. Not gonna happen though .

I think you've got a good list. If I had to rank them in order of competitiveness:
1. Gardner
2. Tillis
3. Collins (Open)
4. Perdue (Open)
5. Perdue (Reelection)
6. Ernst
7. Sullivan
8. Daines
...
9. Capito
10. Collins (Reelection)
...
11. Cornyn (Open)
12. Roberts (Open)
13. Cornyn (Reelection)
14. Roberts (Reelection)

[SCNCmod]

Everyone tends to completely dismiss TX... but I think Cruz is definitely in danger if Joaquin Castro decides to run.  TX has low off-year turn out, Is now a Minority- Majority state (and such  a high profile Mexican-American candidate would motivate turnout), and Cruz is particularly divisive.

So I say TX (in addition to NV & CO) ... and 2 in Puerto Rico if they achieve Statehood!

[Coraxion]

1. Gardner
2. Susan Collins (only if she retires)
3. Tillis
4. Daines
5. Perdue
6. Shaheen
7. Sullivan
8. Warner

[Pragmatic Conservative]

1. Colorado (Gardner)
2. North Carolina (Tillis)
3. Georgia (Perdue)
4. Montana (Daines)
5. Alaska (Sullivan)

Maine goes to #1 if Susan Collins either resigns her seat if she runs/wins a potential governor race or retires.

[Heisenberg]

1. Gardner
2. Susan Collins (only if she retires)
3. Tillis
4. Daines
5. Perdue
6. Shaheen
7. Sullivan
8. Warner

Basically mine, but erase Purdue and add Peters before Warner

For the purpose of this, it's asking about R-held seats.

[Cactus Jack]

From most to least likely to flip, and assuming Collins does not retire:

1. Colorado (Likely D)
2. North Carolina (Pure Tossup)
3. Montana (Pure Tossup)
4. Alaska (Tilt R)
5. Georgia (Tilt R)
6. Iowa (Lean R)
7. Kansas (Likely R)
8. Louisiana (Likely R)
9. Mississippi (Likely R)

Yeah, thereabouts, though I'm really not sure who could defeat Daines on the Democratic bench.

[Cactus Jack]

From most to least likely to flip, and assuming Collins does not retire:

1. Colorado (Likely D)
2. North Carolina (Pure Tossup)
3. Montana (Pure Tossup)
4. Alaska (Tilt R)
5. Georgia (Tilt R)
6. Iowa (Lean R)
7. Kansas (Likely R)
8. Louisiana (Likely R)
9. Mississippi (Likely R)

Yeah, thereabouts, though I'm really not sure who could defeat Daines on the Democratic bench.

The term-limited Governor who consistently posts high approval ratings

I'm not sure why I keep forgetting Bullock's entire existence.

[I’m not Stu]

What would happen in the unlikely scenario Moore Capito retires?

[Pragmatic Conservative]

What would happen in the unlikely scenario Moore Capito retires?

Republican hold either way, West Virginia is too Republican to support a non incumbent Democrat in a Senate race.

[I’m not Stu]

What would happen in the unlikely scenario Moore Capito retires?

Republican hold either way, West Virginia is too Republican to support a non incumbent Democrat in a Senate race.

What about Jim Justice? WV voted for a non-incumbent Democratic governor in 2016, where Trump won every county. Would Justice lose to a weak candidate like John Raese?

[Kamala]

What would happen in the unlikely scenario Moore Capito retires?

Republican hold either way, West Virginia is too Republican to support a non incumbent Democrat in a Senate race.

What about Jim Justice? WV voted for a non-incumbent Democratic governor in 2016, where Trump won every county. Would Justice lose to a weak candidate like John Raese?

I mean I doubt Raese would win the nomination, since it's likely that, out of Jenkins and Morrisey, whichever didn't get the nom in 2018 would likely be a shoe-in for 2020.

[Pragmatic Conservative]

What would happen in the unlikely scenario Moore Capito retires?

Republican hold either way, West Virginia is too Republican to support a non incumbent Democrat in a Senate race.

What about Jim Justice? WV voted for a non-incumbent Democratic governor in 2016, where Trump won every county. Do you think incumbent Joe Manchin loses in 2018?

Manchin will probably win re-election but that is largely because he is personally popular (though certainly not safe). Governor and state elections are fairly disconnected from state elections, so you can have a Democratic governor like Justice in West Virginia and a Republican governor like Hogan in Maryland.

[Xing]

Colorado
(Maine if Collins retires)
North Carolina
Iowa
Georgia
Montana
Alaska

[Cynthia]

1. Maine Open (Lean/Likely D)
2. Colorado (Tilt/Lean D)
3. North Carolina (Tossup/Tilt R)
4. Iowa (Tilt R)
5. Georgia Open (Tilt R)
6. Montana (Tilt/Lean R)
7. Georgia Reelection (Lean R)
8. Alaska (Lean R)
9. Maine reelection (Lean/Likely R)
10. Kansas (Lean/Likely R)
11. Texas Open (Likely R)
12. West Virginia (Likely/Safe R)
13. Texas reelection (Likely/Safe R)
14. Louisiana (Likely/Safe R)
15. Mississippi (Likely/Safe R)

[SCNCmod]

Everyone tends to completely dismiss TX... but I think Cruz is definitely in danger if Joaquin Castro decides to run.  TX has low off-year turn out, Is now a Minority- Majority state (and such  a high profile Mexican-American candidate would motivate turnout), and Cruz is particularly divisive.

So I say TX (in addition to NV & CO) ... and 2 in Puerto Rico if they achieve Statehood!

I just realized the post was asking about 2020... not 2018...

regarding 2020 predictions...

Dem win/ Lean Dem
Thom Tillis: Tillis 100% loses to state senator Jeff Jackson
Cory Gardner: Likely Dem
Dan Sullivan: I could see a Dem winning Alaska... leans Dem

Toss Up
David Perdue: Dems could win with the right candidate.... Toss Up
Shelley Moore Capito (if Jim Justice runs): Not sure... so Toss-up?
Steve Daines (Steve Bullock might run)Not sure... so Toss-up?

Repub win/ Lean Repub
Joni Ernst: Ernst will be safely re-elected
John Cornyn: This seat will be safely Repub (Dem best chance in TX is 2018 Joaquin Castro vs Cruz)
Pat Roberts (likely retires): Kansas will stay Republican
Susan Collins (possibly retires): Collins Stays & easily wins

[I’m not Stu]

Everyone tends to completely dismiss TX... but I think Cruz is definitely in danger if Joaquin Castro decides to run.  TX has low off-year turn out, Is now a Minority- Majority state (and such  a high profile Mexican-American candidate would motivate turnout), and Cruz is particularly divisive.

So I say TX (in addition to NV & CO) ... and 2 in Puerto Rico if they achieve Statehood!

I just realized the post was asking about 2020... not 2018...

regarding 2020 predictions...

Dem win/ Lean Dem
Thom Tillis: Tillis 100% loses to state senator Jeff Jackson
Cory Gardner: Likely Dem
Dan Sullivan: I could see a Dem winning Alaska... leans Dem

Toss Up
David Perdue: Dems could win with the right candidate.... Toss Up
Shelley Moore Capito (if Jim Justice runs): Not sure... so Toss-up?
Steve Daines (Steve Bullock might run)Not sure... so Toss-up?

Repub win/ Lean Repub
Joni Ernst: Ernst will be safely re-elected
John Cornyn: This seat will be safely Repub (Dem best chance in TX is 2018 Joaquin Castro vs Cruz)
Pat Roberts (likely retires): Kansas will stay Republican
Susan Collins (possibly retires): Collins Stays & easily wins

Lean D
Cory Gardner

Tossup
Steve Daines: if Steve Bullock runs
Shelley Moore Capito: if Jim Justice runs
ME: if Collins retires
Thom Tillis

Lean R
Joni Ernst
Dan Sullivan
David Perdue
TX: If Cornyn Retires
Steve Daines: If Bullock Doesn't run

Safe R
Shelley Moore Capito: If Justice doesn't run
TX: If Cornyn runs
ME: If Collins runs
Pat Roberts

[Ye We Can]

Who do Colorado Dems have lined up against Gardner?
Not disagreeing with his vulnerability, just asking.

[President Punxsutawney Phil]

Who do Colorado Dems have lined up against Gardner?
Not disagreeing with his vulnerability, just asking.

Hickenlooper?

[President Punxsutawney Phil]

Yeah, thereabouts, though I'm really not sure who could defeat Daines on the Democratic bench.

Pretty much any competent Democratic, actually. Cooney, Bullock, Laslovich, etc. Saying that Daines is heavily favored is just asking for him to lose.

Who wouldn't count as 'competent Democrat'?

[Cactus Jack]

Yeah, thereabouts, though I'm really not sure who could defeat Daines on the Democratic bench.

Pretty much any competent Democratic, actually. Cooney, Bullock, Laslovich, etc. Saying that Daines is heavily favored is just asking for him to lose.

Who wouldn't count as 'competent Democrat'?

Rob Quist, presumably.

[Coolface Sock #42069]

Everyone tends to completely dismiss TX... but I think Cruz is definitely in danger if Joaquin Castro decides to run.  TX has low off-year turn out, Is now a Minority- Majority state (and such  a high profile Mexican-American candidate would motivate turnout), and Cruz is particularly divisive.

So I say TX (in addition to NV & CO) ... and 2 in Puerto Rico if they achieve Statehood!

Cruz's seat is not up that year.

[TheSaint250]

CO, NC, ME (if Collins retires)

I don't think IA will be too much at risk of switching, but it could happen

[I’m not Stu]

Everyone tends to completely dismiss TX... but I think Cruz is definitely in danger if Joaquin Castro decides to run.  TX has low off-year turn out, Is now a Minority- Majority state (and such  a high profile Mexican-American candidate would motivate turnout), and Cruz is particularly divisive.

So I say TX (in addition to NV & CO) ... and 2 in Puerto Rico if they achieve Statehood!

Cruz's seat is not up that year.

Joaquin Castro might have a chance if Cornyn retires.