I see someone on here likes Congressman Aaron Schock of the 18th district of Illinois. I think he will be a frontrunner in the 2020 election. (He is only 27)
My "dark horses" are
1. John Thune; Junior Senator from South Dakota
2. Sam Brownback; Current Senator and candidate for Kansas governor
Finally! A blue avatar from Indiana. Welcome to the forum, fellow Hoosier.
I don't consider Thune a dark horse...I consider him a serious contender. And you know, Brownback may well re-emerge. He is a guy with too much potential to retire from public life at this early stage. I don't like or agree with either of them, but they are fairly sharp guys.
(My money's still on Pence.)