The 2020 CO US Senate Race will give Democrats majority control of the US Senate.

2017
Democrats narrowly lose AL(Jones-D) on Tuesday.
2018
Democrats win by a landslide margin.
CA-Feinstein-D 23
CT-Murphy-D 24
DE-Carper-D 25
HI-Hirono-D 26
ME-King-I/D 27
MD-Cardin-D 28
MA-Warren-D 29
MI-Stabenow-D 30
MN-Klobuchar-D 31
NM-Heinrich-D 32
NY-Gillibrand-D 33
RI-Whitehouse-D 34
VT-Sanders-I/D 35
WA-Cantwell-D 36
Democrats win by a low double digit margin.
MN-Swanson-D 37
NJ-Menendez-D 38
PA-Casey-D 39
VA-Kaine-D 40
Democrats win by a high single digit margin.
AZ-Sinema-D 41(Ward-R is the Republican nominee)
MT-Tester-D 42
NV-Rosen-D 43
ND-Heitkamp-D 44
WV-Manchin-D 45
WI-Baldwin-D 46
Democrats win by a narrow margin
FL-Nelson-D 47 vs Scott-R
IN-Donnelly-D 48
MO-McCaskill-D 49
OH-Brown-D 50
Democrats will have a 50-50 tie in the US Senate after 2018
2020
Democrats hold onto
DE-Coons-D 40
IL-Durbin-D 41
MA-Markey-D 42
MI-Peters-D 43
MN-Swanson-D 44
NH-Shaheen-D 45
NJ-Booker-D 46
NM-Udall-D 47
OR-Merkley-D 48
RI-Reed-D 49
VA-Warner-D 50
Republican held US Senate seat Democrats will pick up in 2020.
CO-Hickenlooper-D or Perlmutter-D 51
Republican held US Senate seats that will be in a Tossup collumn.
AZ(McCain-R) Kelly or Stanton-D vs McSally-R
MT- Bullock-D vs Daines-R
NC-Foxx-D vs Tillis-R