AUGUSTA — Brunswick Democrat David Costello is entering the race to unseat Republican Sen. Susan Collins in 2026.

Costello ran just last year against independent Sen. Angus King and says he’s hoping to unseat Collins because he wants to fight back against the Trump administration.

Costello has worked in state, local and federal government and is a native of Old Town. He’s one of several people seeking to challenge Collins, who is seeking her sixth term.

In a statement, Costello says he’s running “to end the Trump Administration’s and Republican Congress’s reckless assault on our democracy, environment and economy.”

Costello, 65, previously worked at USAID, which provides help to foreign nations and was a senior aide to the Maine Secretary of State, mayor of Baltimore, and governor of Maryland, according to his campaign.

Several other Democrats have filed to run for the seat, including Jordan Wood, Natasha Alcala, Andrea LaFlamme and Tucker Favreau, according to the Federal Election Commission.

On the Republican side, in addition to Collins, Carmen Calabrese and Daniel Smeriglio have also filed.

The first to mount a challenge to Collins was independent Philip Rench, who announced a run in February.

Costello said he believes the 30 years he spent working in government gives him the best chance of defeating Collins.

“I believe I have the broadest and most fitting knowledge and experience to defeat Senator Collins in 2026 and best represent Maine in the United States Senate,” he said.