I don't know, Nate.  I admire your work and your lucid explanations of polls and their import.  But this doesn't make any sense.  You are contradicting yourself.  To say that PA is "in play" in the event of a sudden, nationwide meltdown of Obama's lead is not at all what people mean, or understand you to mean, by "PA is at this moment 'in play'."

The last three polls of the state, which do show a tightening (4, 6, and 7 points), still all show Obama with 51 or 52%. So, McCain appears to be picking up a lot of late deciders, but he hasn't been cutting into Obama's numbers. As long as he's not flipping votes, that shouldn't be terribly worrisome. The discussion of whether undecideds go heavily toward McCain nationally has been discussed quite a bit. Most pollsters don't see any reason to think they will. My pessimistic gut says otherwise. That could have implications for several of the states that are still up for grabs, but Obama is over 50% in enough of them that it shouldn't cost him the election even if ALL of the undecideds go to McCain. And, of course, if the polls are making conservative assumptions about turnout and Obama's turnout machine is actually effective, the current polling could be overwhelmed and Obama could win bigger than the polls can predict.

I feel  sorry for Nate Silver. Aside from presenting and interpreting poll numbers, he has decided to undertake the mammoth job of reassuring an audience that has grown neurotic after watching Gore and Kerry lose close campaigns. His in-box must be filled with emails that could be used to get the sender committed to an asylum. The in play versus "in play" distinction strikes me as something he would not have to explain if his readers weren't chewing through their fingernails every night. He's become an electoral psychologist for liberals, so we should cut him some slack. Without 538.com, I would have drown in cynicism and doubt a long time ago. I hope he doesn't disappear when the election ends and look forward to reading the book that I assume he will write.

I don't believe Nate has claimed he can forecast how voters will behave on election day. He can only take the data from multiple polls and provide us will a daily number and assign a probability to the number. Pennsylvania is only significant because it is the state that McCain deemed necessary to win as he has placed it "on his path". Or, in Nate's words "because those are the only scenarios wherein John McCain can win.". Yes, all states or at least a combination of other states have the potential to shift and in fact a win in PA is not sufficient for McCain. It should not be seen as a hedge in the prediction but an admission the race relies upon voters, and the first test will be Pennsylvania.

It would be foolish to deny the dynamics of an election. People in Pennsylvania will vote on the 4th and McCain hasn't ceased campaigning. McCain's task is to manipulate their behavior (again, Nate can't predict his efficiency) but we have been provided with the conditions McCain must meet.

This election is not over. McCain needs to win Pennsylvania or he's probably finished. The current polling data does not favor his strategy but at least we know what McCain must do to keep PA "in play". No voter in any state should quit playing before they vote and John McCain is relying on voters in Pennsylvania to defy the odds that Nate laid down. Do we tell people this is over, don't vote or get off your asses because Pennsylvania is "in play"?

Arlen Specter, yesterday, was saying that people who said "Obama" will vote McCain in the booth.  Arlen Specter, now the Official Purveyor of Bradley Effect in Pennsylvania.  The Republican Party - even the "saner" parts of it like Specter, has lost all moral claim to governance.

icarusr:  In season one of 30 Rock, Tina Fey's Liz Lemon confesses (well before the nominees were even selected) that there was a good chance that she would tell all her friends that she was voting for Obama but secretly vote for McCain.  But that's because her character is "nutburgers" about national security threats.  The joke was funny because it captured, I think, something real about the moment -- Obama was the star but McCain was steady, moderate, and safe in popular imagination.  That moment is long gone.  Obama has convinced the electorate that he's steady, moderate, and safe, and now McCain is the one who's nutburgers.

If the purpose of saying that PA is "in play" is to motivate Obama voters to go vote, then Amen!, PA is in play big time.  That's why the Obama campaign expresses its cautious optimism/concern about PA.  But there does not seem to me to be any sense in which PA is in play any moreso than the entire election.  It is not contrary to the laws of physics that the electorate could get up on November 4 and vote heavily for McCain.  In that sense, everything is "in play" until the election is over.  But if there is nothing more than a miniscule probability that PA will go for McCain without the whole country shifting that way, I still don't see what it means to state that PA is "in play."  That ought to mean that under current conditions the outcome there is more uncertain than not, and that ain't the case.  Seems to me to be a case of rhetorical excess.

To paraphrase the Grand Old Man, to suggest that a 2% chance of one party capturing the state of Pennsylvania puts that state "in play", without or without the inverted commas, may not be done without some risk, at least, of terminological inexactitude.

Jhildner: Agree with you - I am not at all certain that the Bradley Effect, if it ever existed - and Bradley's pollster appears to doubt that it ever did - is real in this election.  The one constant we have seen is that strong supporters of POWPOW and the Palin have no compuctions whatever about expressing their support for the Wanker and the Whank Job, even at the risk of sounding racist and looney tunes.  It is unfathomable to me that in an environment in which someone actually considers it appropriate to carry around a stuffed monkey called "Hussein", where Republican Party leaders continue to question Obama's citizenship and link him to Islam and so on, McCain supporters would somehow feel "ashamed" to say they are voting for the old coot and the pitbull.  It would seem to me that precisely the reverse would be the case: life-long Republicans living in highly conservative and white neighbourhood, would feel some trepidation in acknowledging that they are not only voting the Godless Party, but a n***** to boot.

I don't put stock in polls, in any event; we'll find out soon enough at 7:01 on Tuesday.  If Obama carries NC, it'll be a landslide.