Mills not ready to support Platner. Costello, though still in race, says he would.

Gov. Janet Mills declined to endorse Graham Platner after her exit from Maine’s U.S. Senate race. But, the other, lesser-known Democrat in the running, David Costello, says he’d ultimately back Platner, assuming he himself doesn’t win.

Costello said Platner called him early Thursday shortly after Mills’ announcement and asked for his support. 

“I said, ‘I’m not ready yet,’ but obviously, if he wins, which it looks as though he will, I’ll be there,” Costello said. 

An Old Town native, Costello, who previously served several roles in Maryland government and unsuccessfully ran for independent U.S. Sen Angus King’s seat in 2024, has lagged far behind Mills and Platner in polls and fundraising. 

Mills attributed her decision to end her campaign to the lack of funds she’d been able to raise, though she’d also been trailing in polling. 

The two-term governor has not endorsed her now-former rival. Spokesperson Tommy Garcia said she’s never voted for incumbent Republican U.S. Sen. Susan Collins and won’t in the coming election, either. 

“As Maine’s Governor, she will continue to support Democratic candidates across Maine,” Garcia said in a statement, “and she will continue to hear and watch how Graham Platner works to earn the support of Maine voters, just as she will keep a close eye on Maine’s Congressional and Gubernatorial primaries as well.” 

There will no longer be debates for the Senate primary, as Platner withdrew after Mills ended her bid. Costello said he was disappointed about no longer having debates. 

“I think there’s certainly more discussion and conversation to have, particularly as it relates to policy issues,” Costello said. “I think we could have had some good debates. And, of course, I think it does a disservice to Maine voters.”