SANGERVILLE, Maine — Democrat Alden Smith of Sangerville announced Wednesday that he has filed paperwork to run for Maine’s 2nd District U.S. House seat.

In June, Rep. Michael Michaud, D-Maine, who has held the seat since 2003, announced that he was seriously considering a campaign for governor, throwing open a scramble for what will be an open seat if Michaud, as expected, runs for governor in 2014.

Smith joins state Sens. Emily Cain of Orono and Troy Jackson of Allagash as announced candidates for the Democratic nomination. Bangor City Councilor Joe Baldacci has said he’s considering a run, and other Democrats, including Secretary of State Matthew Dunlap, have been mentioned as possible candidates.

Smith, 31, served as a Navy officer on the submarine USS Pittsburgh and currently serves in the U.S. Naval Reserves. According to his website, he is a student at the Fletcher School of Law and Diplomacy in Medford, Mass.

In a release, Smith said, “My top priorities in the U.S. Congress will be building a strong economy, providing excellent public education, supporting working families, strengthening labor unions and keeping America safe.”

Announced Republican candidates include Assistant House Minority Leader Alexander Willette, R-Mapleton, who announced his candidacy in July, and Blaine Richardson, who announced earlier this month that he planned to run.

Former House minority leader Josh Tardy, now an influential State House lobbyist, and former treasurer Bruce Poliquin have also have been mentioned as possible contenders for the Republican nomination.

The last Republican to represent the 2nd District was Olympia Snowe, who held the seat from 1979 to 1995, when she became a U.S. senator. Since then, Democrats John Baldacci and Michaud have represented the district, which covers northern and central Maine.

A primary to determine party nominees will be held in June 2014.