Place your bets 2 years out: who will still be a Senator on January 4, 2021?

[pbrower2a]

Cornyn sticks unless Beto O'Roarke runs against him. Daines is iffy.

Tina Smith won  decisively and is no longer an appointed Senator. Peters is in the right state for a Democrat.

Gardner, Collins (now), Jones, and perhaps Ernst are simply wrong for their states. McSally never won her Senate  seat, and probably never will again. Tillis is simply awful, and Georgia demographics are catching up to Purdue.

[TarHeelDem]

-Republicans Cory Gardner, Martha McSally, Thom Tillis, and Susan Collins lose their seats (in order of decreasing likelihood).
-Democrat Doug Jones loses his seat.

Dems net a gain of three seats, win the presidency, and take back the Senate.

[MT Treasurer]

Susan Collins (I doubt Trump loses ME by more than 6 points in 2020, and Collins should be able to overcome to a narrow Trump loss in the state.)
Joni Ernst (not happening short of a massive Democratic wave bigger than 2018)
John Cornyn (probably, but will be relatively close)
Steve Daines (probably, but he’s by no means safe like Atlas seems to think)
David Perdue (tough call, but the 50%+1 rule helps Perdue a little)
Thom Tillis (very tough call. He’ll probably underperform Trump and could very well lose. Gun to my head, he wins if Trump wins reelection and loses if Trump loses reelection.)      
Tina Smith (she’ll probably run 1 or 2 points ahead of the Democratic candidate, and since I don’t think Trump will carry MN in 2020...)
Jeanne Shaheen (very good fit for her state, not sure if Sununu's success can be replicated in a federal race, Trump will most likely lose the state, etc.)

Senators Cory Gardner, Doug Jones, Martha McSally, and Gary Peters lose their seats (in order of decreasing likelihood). Peters was by far my toughest call.

[Vespucci]

But will Democrats have a strong challenger for McSally in AZ, and won't she have incumbency advantage?

Appointed Senators don’t really get incumbency advantage. Also, she just lost an election, and Mark Kelly is a pretty good candidate.

[Xing]

All except for Jones, Gardner, McSally, and (tough call) Tillis.

[S019]

All except for Jones and Gardner, McSally if Kelly is nominee

[nealkp1212]

All US Senators up for re-election in 2020 except for Jones(D-AL), Gardner(R-CO), Tillis(R-NC), McSally(R-AZ) if Kelly is the Democratic nominee,  Perdue(R-,GA) if Abrams is the Democratic nominee, and Daines(R-MT) if Bullock is the Democratic nominee.
Tough call- Ernst(R-IA), Collins(R-ME), and Cornyn(R-TX) if Joaquin is the Democratic nominee.

[100% pro-life no matter what]

Only partisan flips are Alabama (duh), Colorado, and maybe Michigan.