David A Costello

David Costello, 65, is a Democratic candidate for U.S. Senate in Maine for the 2026 primary. Born in Bangor and raised in Old Town in a working-class family, he earned degrees from George Washington University and the London School of Economics. With over 30 years in senior government roles, including environmental policy consulting, Maryland state government, and USAID, he emphasizes his extensive experience. Costello is running to protect democracy, the environment, and the economy, and to ensure Mainers have access to education, housing, healthcare, and job skills. He supports aggressive climate action and aims to defeat incumbent Susan Collins, having previously run in 2024.