A business executive who touted his experiences as a foster child when he announced a primary challenge to Democratic Massachusetts U.S. Sen. Edward Markey in July has ended his campaign.
Steve Pemberton in his emailed announcement Monday said he couldn't overcome a system that favors incumbents.
The 52-year-old Pemberton said while "inspired and energized" by the people he met during his campaign he "ran into an impenetrable wall of legacy and birthright - of incumbency and connections" that stifles many political voices.
Markey served in the U.S. House for 37 years before winning election in 2013 to the Senate seat previously held by Democrat John Kerry.
Markey still faces at least two other primary challengers: U.S. Rep. Joe Kennedy III, grandson of Robert F. Kennedy; and Shannon Liss-Riordan, a workers' rights lawyer.
