David Costello, a Democrat from Brunswick, announced Wednesday that he is joining the race to challenge Republican Sen. Susan Collins next year.
Costello grew up in Old Town and attended the University of Maine, George Washington University and the London School of Economics and Political Science. He worked for the federal international assistance program USAID for nearly 20 years and later held senior staff positions in the city of Baltimore and the state of Maryland, including serving as the acting secretary of the Maryland Department of Environmental Protection.
This is Costello’s second bid for a Senate seat. He finished third behind independent Sen. Angus King and Republican Demi Kouzounas in last year’s Senate race, receiving roughly 11 percent of the vote.
In announcing his campaign on Wednesday, Costello said he is running to “end the Trump administration’s and the Republican Congress’s reckless assault on our democracy, environment and economy.”
“In 2024, I campaigned to strengthen our democracy and bolster the federal government’s ability to address such pressing challenges as climate change; lack of affordable housing and health care; economic inequality; and insufficient retirement security,” Costello said in a statement. “These are challenges the Trump Administration and Senator Collins and her Republican colleagues are either ignoring, or worse yet, exacerbating.”
The 2026 race could become one of the most closely watched and expensive Senate race in the country as Democrats and Republicans battle for control of the chamber. But there is widespread speculation about who Democrats will nominate to challenge Collins, a five-term incumbent. Some state and national Democrats have been urging Gov. Janet Mills to join the race, however she has not indicated her plans.
Three other Democrats — Jordan Wood, Natasha Alcala and Andrea Laflamme — have already filed papers with the Federal Elections Commission to seek the nomination. Other candidates are expected to join the race.
This story appears through a media partnership with Maine Public.
