All indications are that the Republican candidate, Scott Brown, has taken the polling lead, on the eve of the election. I think this will be a nail-biter myself; I have a lot of trouble imagining any Republican cruising to victory in Massachusetts. It’s not impossible, though, and there is reason to think that the Democrats’ filibuster-proof majority will be broken on Tuesday. This will not mean the Democrats will lose their governing majority in Congress; it means that they must pay more than lip service to Republican concerns. Which is as it should be.