Iraq War veteran Seth MoultonSeth Wilbur MoultonMore Dems offer to hire McCabe McCabe is ‘considering all options’ after firing Democrats have shot at flipping the House if they can stay in the center MORE (D) defeated openly gay Republican Richard Tisei (R-Mass.) in a closely watched Massachusetts House race.

Tisei was one of two gay GOP candidates contesting House races this election year.

A former Marine, 36-year-old Moulton defeated nine-term incumbent Rep. John Tierney in the Democratic primary.

Moulton thanked his supporters Tuesday night.

"From the example set by the greatest generation, to answer the call during World War II and continue to serve after they came home. America's newest generation shows renewed and growing commitment to public service," he said in a speech. 

"It is not about what's right for the Democratic Party, or what's right for the Republican Party, it's about what's right for America," he added. 

Tisei conceeded quickly after the race was called.

“Seth has served his country very admirably and very honorably in the military and I’m sure he’s going to do the same as the next Congressman from this district,” Tisei said in a speech Tuesday, according to The Boston Globe. 

This story was updated at 10:18 p.m.