Susan Collins was considered one of the most vulnerable senators up for election this year.
The Democratic Party put a target on her Maine senate seat in 2018 when she voted to confirm Brett Kavanaugh to the Supreme Court.
Democrats raised tens of millions of dollars to defeat her.
However, Collins challenger Sara Gideon, barely got 40% in the general election.
Collins earned over 53% of the vote.
Political analysts consider Collins victory a major humiliation for the Democrats, who worked overtime to oust her.