Obviously, turnout is the single most important factor that will determine whether Martha Coakley actually manages to lose the Massachusetts Senate seat to Republican Scott Brown.
But it's not just about turnout. The Rasmussen poll that just came out -- one which shows Coakley's lead shrinking from 9 to 2 points -- also shows Barack Obama with a 57 percent approval rating (versus 41 percent opposed) among likely voters, and the health care bill favored by 52 percent of likely voters (versus 46 percent opposed).
According to the poll's internals, right now about 8 percent of the electorate both (a) favors health care reform, and (b) has not been brought into Coakley's column. This includes 5 percent of the electorate which favors health care but is planning to vote for Scott Brown, 2 percent for the independent candidate, and 1 percent who favor health care who are undecided.
In addition, about 11 percent of the electorate approve of Barack Obama but are not planning to vote for Coakley.
If this were just about turnout, I would feel relatively safe about Coakley's position. The Democratic establishment has, somewhat belatedly, woken up to the closeness of the race, and polls like these will wake voters up too. And the Democrats have an experienced GOTV team on hand, with veterans from both the Obama and Hillary Clinton campaigns.
But if the Rasmussen numbers are right, there's also a chance that Coakley could lose even with a less-than-worst-case turnout scenario. Although I sometimes have concerns about the tightness of Rasmussen's likely voter screens, the fact is that an electorate which gives a 57 percent approval rating to Barack Obama is one that they ought to be reasonably contented with on election day.
In other words, there are still some swing voters here, and there is still some persuasion to do. And bear in mind that while every new voter that you turn out gets you a +1, every swing voter you persuade is worth a +2, since you're both adding a vote to your own tally and taking one away from your opponent.
Coakley's latest attempt at persuasion -- a commercial tying Scott Brown to the national GOP agenda -- feels like the right tune sung in the wrong key. Voters need to be reminded of just how oppositional the Republicans in Washington have become -- voting with near unanimity against not just the health care reform bill (which the commercial strangely sidesteps) but also the fair pay act for women, the jobs bill, the cap-and-trade bill (which ought to be popular in Massachusetts), the financial regulation bill, and the stimulus package. Then they need to be persuaded that Brown will support that pattern of obstruction and be a pawn in the Republicans' arsenal. Really, then, I'd take this commercial out of rotation and replace it with two separate spots (or one 60-second spot) which tackle the two flavors of the argument in a less compressed way. And Coakley could probably also use a third spot as a closer, which talks more optimistically about the Obama agenda, the Kennedy legacy, and relatively popular upcoming programs like the jobs bill.