To find out more, go to:
http://www.massdems.org/index2… There is a list by county.
There is a “caucus selected” member to balance each popularly elected member. My seat was by popular election; there is also a female member of the State Democratic Committee from the 4th Middlesex chosen by a caucus.
There are therefore parallel routes to a seat on the State Democratic Committee. My impression from the fact that these vacant seats are listed on the State Democratic Committee website is that these seats are “truly” open – but you MUST live in that district.
If my impression is not accurate, I hope one of the experts who read and post on this site will add the rest of the story.