President Donald Trump speaks before signing two prescription drug bills in 2018 that were sponsored by U.S. Sen. Susan Collins of Maine, who is in red. Trump indicated support for the Republican’s 2020 re-election in a Monday tweet. Credit: Susan Walsh | AP

AUGUSTA, Maine — President Donald Trump gave U.S. Sen. Susan Collins of Maine a rare shout-out on Twitter late Monday, promoting a fundraising page for the Republican while calling her re-election crucial for her party’s bid to maintain control of the upper chamber.

Trump said he agrees “100%” with a Friday tweet from Sen. Lindsey Graham, R-South Carolina, that Collins is needed to maintain a GOP majority next year and she showed “unbelievable courage” with her 2018 vote for U.S. Supreme Court Justice Brett Kavanaugh.

Maine’s senior senator announced her run for a fifth term last week, an unsurprising move given that she raised more money than any Maine politician in history by September’s end to gear up for an unprecedented race here that has already seen $10 million in advertising.

Collins refused to endorse Trump in 2016 and opposed Republican bids to repeal the Affordable Care Act in 2017. But her vote Kavanaugh and Republicans’ 2018 tax-cut package have rallied conservatives to the centrist’s defense while animating her Democratic challengers. Collins has largely declined to discuss the process House Democrats’ impeachment of Trump, citing her view that she will serve as a juror in the Senate trial.

Four Democrats — House Speaker Sara Gideon, lobbyist Betsy Sweet, lawyer Bre Kidman and former Google executive Ross LaJeunesse — are running in a June primary for the nomination. Green activist Lisa Savage and independent Danielle VanHelsing have also filed to run.

Trump’s step into the race is likely to make its way into Democratic pitches. Gideon wrote in a Tuesday fundraising email she was taking on “virtually the entire Republican Party establishment,” while Sweet said Collins has “made it abundantly clear which side she’s on, and it’s not ours” — but that of Republican leaders.