Just a little something to keep in mind as you watch returns tonight. There's a reason that Massachusetts's congressional seats are going to remain all, or mostly, in Democratic hands despite whatever number of seats flip from blue to red across the country.
The seats that are likely to flip are not random. They are almost all, in order of vulnerability: 1) open seats; 2) first-term incumbents; 3) districts where McCain beat Obama (many of which have grown increasingly conservative over the incumbent's tenure); or 4) two-term incumbents, who have only won in the '06 and '08 Democratic wave elections.
That can be seen in the National Journal ranking of 83 most vulnerable Democratic-held seats. Only 8 of the 83 meet none of those four criteria, and those are mostly bunched at the bottom of the list, as relatively safe.
Not coincidentally, the only Massachusetts district on that list is the open 10th, which is #64.
The only other Massachusetts race that fits any of the criteria is 2nd-termer Niki Tsongas.
Bear in mind that districts with those vulnerabilities tend to inspire better Republican candidates to run, and more money and support to help that challenge -- which increases the likelihood of turning the seat red, in a sort of self-fulfilling prophesy. The Massachusetts districts, for the most part, did not stand out as winnable for Republicans early on, and thus did not draw the most powerful challengers.
And yet, many insiders I talk to fully expect that many of the state's incumbents will win by fairly narrow margins -- getting under 60%, and in some cases under 55%, of the vote. Meanwhile, Democrats may very well win the open 10th, but if so only because of enormous gaping flaws in the Republican candidate.
I guess what I'm saying is that if Democrats do hang onto all their Congressional seats today, it won't necessarily be because the GOP wave skipped the state, but because conditions weren't quite right for that wave to breach the barriers -- this time.