Here's where things stand: four polls released in the last 48 hours all show Scott Brown leading Martha Coakley by anywhere from three to ten points. (UPDATE: Daily Kos just released a survey from R2000 conducted Fri-Sun showing Coakley now tied with Brown at 48% a piece. Putting that in context with R2000's survey for Blue Mass Group taken last Tuesday and Wednesday, Coakley has lost one point and Brown has gained seven.)

But there's still quite a bit of variance in the polls, including two surveys conducted in the last week showing Martha Coakley leading by either two or eight points.

Among the issues involved in using polls to assess the state of the race are that a couple of the polling firms are brand new, and a handful of the surveys were conducted on behalf of partisan affiliated organizations.

For example, the Democratic Blue Mass Group's poll, conducted by Research 2000 (who conducts all of Daily Kos's surveys) shows Martha Coakley up eight points. (See update above...)

On the other hand, the Democratic firm PPP - which had a very good track record in the 2008 cycle - shows Brown extending his lead from 1 point last week to five points this week. And the conservative media outlet Pajamas Media has a poll by the Republican firm CrossTarget showing Brown up 10 points - though that represents a five point decline for Brown from their survey last Thursday.

So is Brown extending his lead? Or is his lead shrinking? Or does he even have a lead in the first place?

Variance in the polls primarily comes from pollsters making assumptions about the following two questions: How many people will turnout on Tuesday and what will the composition of the electorate look like. Obviously, those assumptions become much more difficult in the case of a special election  - and more difficult still in a special election that has been suddenly nationalized in the final 10-14 days of the race.

But - and this is probably the most salient point of all - ALL of the polls have one thing in common: they all show support for Martha Coakley is under 50%. Even the most favorable poll for her in the bunch - the aforementioned Blue Mass Group survey - shows her at 49%.  That is a critical sign of weakness for her candidacy in a state where Democrats outnumber Republicans by a three-to-one margin.

That is why inside the Beltway handicappers like Charlie Cook moved this race to a toss up late last week - and Stuart Rothenberg went a step further just this morning moving the race to lean Republican takeover.

Could all of the polls and pundits be wrong? Of course they could (see, New Hampshire, Democratic Primary 2008). But the preponderance of available evidence, including the public polling data and most of the anecdotal information flowing out of the Bay State, suggests that Scott Brown has an edge heading into tomorrow's vote.

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