WASHINGTON (Reuters) - Seth Moulton, an Iraq War veteran and Democratic congressman from Massachusetts, entered the 2020 presidential nomination contest on Monday, swelling the ranks of declared contenders to almost 20, his campaign announced in a video posted on YouTube.

He enters the race as an underdog, with little national name recognition and a shorter track record than some of his opponents who have spent years in the U.S. Senate or as state governors.

But Moulton, 40, has already built a political career driven by challenging the party’s establishment.

“Decades of division and corruption have broken our democracy and robbed Americans of their voice,” he said in the video, which was released early on Monday.

“While our country marches forward, Washington is anchored in the past,” he said.

Moulton was first elected to Congress in 2014 after mounting a primary challenge against John Tierney, a fellow Democrat who had held his seat for 18 years.

After Democrats took control of the U.S. House of Representatives in 2018, Moulton led an unsuccessful effort to remove Nancy Pelosi as the party’s leader in the chamber.

“Tough conversations make us stronger, not weaker, and we need to keep having them if we’re going to deliver on the change that we’ve promised the American people,” Moulton said in a statement announcing the end of his opposition to Pelosi.

In the video, Moulton said he wants to tackle climate change and grow the U.S. economy by promoting green jobs as well as high tech and advanced manufacturing jobs.

“I’m running because we have to beat Donald Trump,” he said.

Moulton served in the Marines from 2001 to 2008. During his 2014 congressional bid, he became a vocal critic of the Iraq War in which he served, saying no more troops should be deployed to the country.

He also has advocated stricter gun laws, saying military-style weapons should not be owned by civilians.

Moulton supports the legalisation of marijuana and told Boston public radio station WGBH in 2016 that he had smoked pot while in college.

He graduated from Harvard University with an undergraduate degree in physics in 2001 and returned to receive a master’s degree in business and public policy in 2011.

For a graphic of the 2020 presidential candidates, see: https://tmsnrt.rs/2Ff62ZC

(Reporting by Ginger Gibson; additional reporting by Rich McKay; Editing by Colleen Jenkins, Jonathan Oatis and Kirsten Donovan)