As I briefly mentioned the other week (scroll down a bit), if Ed Markey is going to be successfully challenged in a Dem primary, it’s likely going to come from his left, not the center. Sure enough, Scott Van Voorhis reports on a rumor that U.S. Rep. Ayanna Pressley is “eyeing a potential challenge to Markey, presumably from his left.” … If she’s not considering it now, she’d be nuts not to consider it eventually. She’s already knocked off one incumbent Dem to get to where she is today. Why not another? … And I think she could beat Markey in a primary showdown, largely by appealing to young voters and reminding people of another 80-something guy who hung around too long.