Massachusetts Senate Race Gets New Challenger
Campaign highlights generational change, criticizes Markey's age and tenure.
Moulton promotes affordability, universal health care, climate action, and assault weapon bans.
Moulton's background includes Marine Corps service, high-speed rail, and 988 mental health lifeline.
Race is top Democratic primary, possibly drawing Ayanna Pressley.
Early polls show Moulton leads Markey 43% to 21% among likely voters.
3 weeks ago