[kiryandil]

Roy Blunt (Mo.), Richard Burr (N.C.), Shelley Moore Capito (W.Va.), Bill Cassidy (La.), Susan Collins (Maine), John Cornyn (Texas), Joni Ernst (Iowa), Lindsey Graham (S.C.), Mitch McConnell (Ky.), Lisa Murkowski (Alaska), Rob Portman (Ohio), Mitt Romney (Utah), Thom Tillis (N.C.), Pat Toomey (Pa.) and Todd Young (Ind.).

[Lurkinanloomin]

Roy Blunt (Mo.) retiring
Richard Burr (N.C.) retiring
Shelley Moore Capito (W.Va.) Trump endorsed
Bill Cassidy (La.) Trump endorsed
Susan Collins (Maine) Trump endorsed
John Cornyn (Texas) Trump endorsed
Joni Ernst (Iowa) Trump endorsed
Lindsey Graham (S.C.) Trump endorsed
Mitch McConnell (Ky.) Trump endorsed
Lisa Murkowski (Alaska) Trump endorsed a challenger
Rob Portman (Ohio) retiring
Mitt Romney (Utah) Trump endorsed
Thom Tillis (N.C.) Trump endorsed
Pat Toomey (Pa.) retiring
Todd Young (Ind.) Trump endorsed

[kiryandil]

retiring in 2022
===================
Roy Blunt (Mo.) 
Richard Burr (N.C.) 
Rob Portman (Ohio) 
Pat Toomey (Pa.) 

re-elected in 2020 (not up till 2026)
==================
Susan Collins (Maine) 
John Cornyn (Texas) 
Mitch McConnell (Ky.) 
Shelley Moore Capito (W.Va.) 
Bill Cassidy (La.) 
Thom Tillis (N.C.) 
Lindsey Graham (S.C.) 
Joni Ernst (Iowa)

up in 2022 (this year)
======================
Lisa Murkowski (Alaska) 
Todd Young (Ind.) - the Repukes might be throwing this one

up in 2024
==========
Mitt Romney (Utah)  [uncertain about his political future]

Richard Shelby, who's retiring this year, didn't stab us in the back. He may have to consider his understudy, Katie Britt.