No more waffling...yes I know this is an extremely close race (unless the polls have utterly missed some dynamic which is very possible) and all depends on turnout, the energy of voters and any last day surprises that may occur. The situation is very fluid - that statement is not exactly rocket science, but is an apt one for this situation.
Out on a limb...ok, jump!
It is also possible, but less likely that either of these candidates wins by a margin of five or more points. Explanation for all scenarios below...
Why Brown wins
Brown has campaigned as an outsider vs. Coakley's insider status. This has energized many independents (quite of few of whom were Obama voters in 2008). Outsider status during a recession with a sizable portion of the electorate angry at Beacon Hill and disappointment with the Obama administration (though not him personally) is a huge plus. Coakley is the defacto "incumbent" in this race and Brown has been able to capture the mantel of the fresh-faced challenger.
Brown also has run a generally positive campaign. He has done a decent job in defining himself and that has helped make this a competitive race. Likeabilty matters.
Voter anger at Beacon Hill and Washington DC - 'nuff said. Running against the "machine" was a smart strategy. The way health care has been debated in DC also has energized his voters. Even in Massachusetts, the current proposals on Capitol Hill are not very popular.
Brown has been able to appeal to lunch bucket Democrats. He won't come close to winning Democrats, but if he can win 20% of them and rack up big margins among independents, it will carry him over the line.
Momentum - he has it. His voters are extremely energized and passionate about his candidacy. Coakley's voters simply are not as energized.
Money - although at a slight financial disadvantage, Brown has been able to remain very competitive and has run a very good GOTV (get out the vote) operation and has been able to advertise on TV, radio, and via robo-calls.
Many folks who may prefer the Libertarian Kennedy may in the booth go for Brown. Third party candidacies typically do much better in opinion polls than in the actual results.
Coakley has run literally one of the worst campaigns that I have ever seen. She is now relying on party unity to carry her over the finish line and is making few as possible media appearances due to her numerous gaffes over the past week. Her campaign really imploded and allowed Brown to climb into this by her not actively campaigning during the month of December. This allowed Brown to define himself instead of her using her considerable financial resources to define him as he was an unknown quantity to most voters.
Coakley's final crash began with the last debate where her rather mundane performance reinforced why she has been avoiding many public forums. Her answers on terrorism (no Taliban in Afghanistan) were interpreted as as being both woefully out of touch and uninformed. I know what she "meant" by her answer - that we needed to redirect our focus to Pakistan and Yemen. However, she created a perception of not being engaged in reality - especially two weeks after a near disaster in the skies over Detroit.
She simply is not a good "politician" although that has nothing to do with her potential performance as senator. But you need to win voters on the ground and little things like being perceived to be surrounding herself with insiders is not the way to win independents. She needed to campaign as a populist and as the heir to Ted Kennedy. She really failed on that account.
Coakley's negative firestorm may attract hard-line Democrats, but I think may alienate independents. Her ads are giving no reason why people should vote for her - they are about portraying Brown in as negative a light as possible. negative ads can and do work, but the saturation bombing smacks of desperation.
How Coakley can win
Turnout turnout turnout! Did I mention turnout? She needs to energize her base. The Democrats enjoy a huge advantage (37% of the electorate are registered Democrats). Labor and human services/advocacy groups have a considerable presence in Massachusetts and they do vote in high numbers.
The negative ad campaign may drive away suburban women from Brown over the abortion issue. It also "gins up" turnout among base Democrats who may have had less reason to vote if they thought Coakley had a comfortable lead.
President Obama's visit (he has to come; if he doesn't and Coakley loses he will share the blame for not helping). This will likely energize minority and urban voters who otherwise may not have shown up.
If all of these things come together, she can win and by a margin that is relatively comfortable. But I think the endemic weakness of her candidacy simply may be too big a drag to pull this off.
Onwards to Tuesday!