Pollster.com: Brown 'likely winner'

Of course, the same factors that make the trend toward Scott Brown so unusual also make the polling challenging and potentially misleading. Brown has moved up so rapidly partly because campaign has been truncated, but the rapid change also prompted a late avalanche of negative advertising by the Democrats directed at Brown. Because it is a special election being held on an usual date, Pollsters have no prior history to judge the size and demographics of the likely electorate. The likely voter problem is one reason why polling errors tend to be larger in special elections.

So while we have the Wofford experience on one hand, we have the lessons of the New Hampshire Democratic primary in 2008 and the special election in New York's 23rd District this past fall on the other. In both cases, candidates surged in the final polls, only to see their apparent leads disintegrate on Election Day. What those races had in common were huge surprise developments that occurred a few days days before the election (Barack Obama's Iowa victory and the withdrawal of Dede Scozzafava) that helped shake up the race, fuel the polling surge and -- perhaps -- provoke voters to focus more closely on their choices and rethink their preferences in the final hours.

Does the nationalization of the Massachusetts Senate race combined with the heavy negative advertising blitz qualify as the same sort of last minute surprise? Perhaps, but it seems like a stretch to me.

Blumenthal reports on the last tracking poll done by the Democrats:

Yes, the internal Coakley campaign poll numbers that have leaked out show a dead even race and perhaps a slight improvement over last week. However, there was more than one internal poll conducted by Democrats A little birdie tells me that the final tracking survey conducted by the Mellman Group for the Democratic Senatorial Campaign Committee had Brown ahead by five points.

So for me it boils down to this: I was a Democratic consultant for long enough to want to believe that Coakley can still prevail, and there is still a remote chance that the polls in this race will be as misleading as they were in New Hampshire. However, my head is not my heart. Barring another polling meltdown, Scott Brown is the likely winner.

Many are expecting an early night but I'm not so sure. A 5 point victory sounds about right from what I've seen which means the networks will probably hold their calls until enough of the popular vote is tallied to be sure.