Washington (AFP) – The already large field of Democratic presidential candidates has grown again: Joe Sestak, a former Pennsylvania congressman with an extensive military background, said Sunday that he plans to seek the presidency.

“I’m Joe Sestak, and I wore the cloth of the nation for over 31 years in peace and war, from the Vietnam and Cold War eras to Afghanistan and Iraq and the emergence of China,” he said in a video announcing his candidacy.

A retired three-star admiral, Sestak represented Pennsylvania’s 7th congressional district for two terms, from 2007 to 2011, and has mounted two unsuccessful runs for the US Senate.

His experience, during his 31-year naval career, included a command position in a region now much in the news: In 2002, he led a carrier strike group during combat operations in the Gulf.

Sestak, whose father was a navy man, also served on the national security staff under President Bill Clinton. He holds a doctorate in government and political economy from Harvard.

Sestak has a reputation as something of a maverick and party outsider.

He is pro-choice, supports gun control, and backed the 2015 Iran nuclear deal.

Sestak’s late entry into an already crowded field — which he said came after his daughter’s brain cancer returned — will complicate his path forward.

Along with three other candidates, he missed the cutoff to be included in the first two televised debates, which will feature 20 Democratic candidates and be held on Wednesday and Thursday in Miami.

But Sestak, the grandson of a Slovakian emigre ironworker who grew up in a working-class suburb of Philadelphia, has a reputation as a tireless campaigner.

During his 2016 campaign, he walked 285 miles (460 kilometers) alone across the entire state of Pennsylvania.

A New York Times reporter, trailing Sestak during his unsuccessful 2010 run for a Senate seat, described his approach to campaigning as “somewhere between tireless and maniacal.”