What was the (largely discredited) Bradley effect? 3%.

During the primaries, a number of pollsters overestimated Obama’s percentage by what? Usually 3 points.

So we can determine from both that any state where Obama’s now 4 points ahead, he’ll likely win. Doing that, he easily wins. So let’s set a higher hurdle for him.

Let’s just go with the most accurate pollsters. And let’s move the margin to 6%.

Compared to Kerry, Obama would pick up NM, IA and OH and he’d lose MN. Which would give him 274 Electoral Votes and the presidency.

So that’s the margin McCain would have to make up in one day, in Ohio: 6%, while winning every state closer. (The margins in NM and IA are even wider, so they’re untouchable.)

That’s a pretty narrow window for a McCain upset.

If McCain won everything 4% or closer, Obama would also pick up CO for a 283 EV win.

And what if we gave McCain every state where he’s behind by 3% or less today? Obama would win VA (13), and NV (5) for a 301 EV win.

And the national polls look even darker for McCain today than they did yesterday. Rasmussen says 52% - 46%. Gallup says 55% - 44%. Ipsos-McClatchy 50% - 42%. Zogby 50.9% - 43.8%. Marist 53% - 44%. Hotline 50% - 45%. GWU 50% - 44%. And even Fox News says 50% - 43%. ALL OF THEM show Obama’s lead widening as the undecideds start rolling in.

Demographically, Obama’s winning ALL education levels, ALL regions (yes, even the South by 47%-46%) and most other demographic distinctions. There’s only 3 that McCain’s going to win: voters over 65 (pre-boomers), Republicans and white males. Almost: Independents have now switched back to give McCain a 32% - 24% lead, the only trend anywhere in the final week that can give McCain any encouragement. And most of that change was caused by Indies moving back to undecided, as McCain only picked up 2% of them.

The only usually reliable pollster picking up McCain-friendly trends beyond that small shift in Independents is SurveyUSA, which shows a lot of tightening in VA, OH and MN. But McCain would have to win VA plus OH plus every other contested state (except PA and NH, which even SUSA gives to Obama, and most analysts consider SUSA’s MN result to be an outlier, far from any other poll).

So again, McCain’s upset window is very narrow.

So yeah, we’d all better keep up the GOTV effort, especially Democrats in FL, OH, VA, MN, CO, IN, NV, GA, AZ, and perhaps ND and MT. Let’s shut that window completely.

By 7:30 pm Eastern tomorrow night, polls will be closed in the contested states of IN, OH, VA, NC, GA and FL. And by 8 pm Eastern, NH, PA and MO will be closed. Watching just those to be certain that Obama wins NH and PA, all he needs from the other seven is just one. So the odds are high that by 8:30-9:00 Eastern, we’ll know the national outcome. (All the poll closing data was compiled beautifully by DavidNYC at Swing State Project, including pointers to key Senate and House races, as well.)

Extra-special links about McCain’s secret plan to upset:

Utilize the poor.

Let Cindy off her leash.