The Politicus 
Assume all other seats are safe for either party besides the toss-up seats below, the Democrats will need to hold:
- AL Doug Jones
- MI Gary Peters
- MN Tina Smith
- NH Jeanne Shaheen
- NM Tom Udall [*Incumbent not running for re-election in 2020.]
- VA Mark Warner
And flip 4 out of the 12 to take over the majority:
- AZ Martha McSally
- CO Cory Gardner
- GA Johnny Isakson [*Incumbent not running for re-election in 2020.]
- GA David Perdue
- IA Joni Ernst
- KS Pat Roberts [*Incumbent not running for re-election in 2020.]
- KY Mitch McConnell
- ME Susan Collins
- MS Cindy Hyde-Smith
- MT Steve Daines
- NC Thom Tillis
- TX John Cornyn
Right now there are 11 Republican seats that are very likely to stay in Republican hands and 6 Democratic seats that are very likely to stay in Democratic hands. This means the Democrats will need to win 3 out of the 12 current Republican seats from the toss-up list above to tie or 4 seats to take over the majority. Of course, we will need to hold all of our toss-ups seats.
