Vulnerable US Senate seats up in 2020 from the most vulnerable to the least vulnerable.

1)CO(Gardner-R) Whoever wins the 2020 Democratic Primary for the CO US Senate Election will defeat Gardner-R in the November General Election by at least high single digit margin.
2)AZ(McSally-R) The likely Democratic nominee (Mark Kelly-D) defeats McSally-R by a narrow to high single digit margin.
3)NC(Tillis-R) Whoever wins the 2020 Democratic Primary for the NC US Senate Election will defeat Tillis-R in the November General Election by a narrow to high single digit margin.
4)AL(Jones-D) It all depends on whether or not Roy Moore-R winning the Republican nomination or endorsing the Republican nominee.
5)ME(Collins-R) It all depends on who and how strong the Democratic Nominee is.
6)GA(Perdue-R) It all depends on who and how strong the Democratic Nominee is.
7)IA(Ernst-R) It all depends on who and how strong the Democratic Nominee is.
8)MI(Peters-D) Peters-D wins re-election by a narrow to high single digit margin.
9)TX(Cornyn-R) Cornyn-R wins re-election by a narrow to high single digit margin.