REPUBLICAN
A Trump Republican says hell challenge Susan Collins from the right in 2020
https://bangordailynews.com/2019/03/25/politics/daily-brief/a-trump-republican-says-hell-challenge-susan-collins-from-the-right-in-2020/
DEMOCRAT
Maine House Speaker Sara Gideon is latest to challenge GOP Sen. Susan Collins in 2020 race
https://www.cnbc.com/2019/06/24/sara-gideon-challenges-susan-collins-in-2020-maine-senate-race.html
Well Collins has nothing to fear from him. Hopefully a challenger with a better chance will jump in.