Seth Moulton is a Marine veteran who served four tours in Iraq before entering politics, bringing a military perspective to Democratic politics that sometimes puts him at odds with his party's progressive wing. He gained national attention as one of the younger Democrats who challenged Nancy Pelosi's leadership in 2018 and has been a vocal advocate for reforming how the party approaches national security and veterans' issues. Moulton briefly ran for president in 2019, positioning himself as a pragmatic centrist who could appeal to swing voters, though his campaign failed to gain traction. He's known for his willingness to break with party orthodoxy on issues like military spending and has carved out a niche as a defense-minded Democrat who emphasizes electability and winning back working-class voters.