With an eye toward today's U.S. Senate election in Massachusetts, the Gallup Organization's Frank Newport has posted a useful piece describing political allegiance there. Aggregating Gallup's 2009 data, it shows that this oft-described "bluest of blue" states has no more self-identified Democrats than the country overall - rather, fewer Republicans and more independents.
Those independents disproportionately lean toward the Democratic Party, giving Massachusetts a net of 9 points more "leaned" Democrats than the country as a whole. (No coincidence, then, that President Obama’s been, on average, 10 points more popular in Massachusetts than nationally.) On one hand this gives the Democrats the clear advantage in the commonwealth; on the other, as Newport suggests, the lack of firm committment to the party helps explain why three of the state’s last four elected governors were Republicans.