I thought about simply cutting and pasting last week's post, or the previous week's
that, or the one before that.... The data aren't changing much, but
what shifts in state-by-state there are tend to favor Obama a little
more. We're at a lull in poll movement. As usual, I'm using composite
polling data from Votemaster Andrew Tanenbaum's www.electoral-vote.com
as input to two simulations, one using a 4% margin of error (the
standard for most state polls), and another using a 12.25% margin of
error (the current value I get from a linear regression of the 2004
state-by state polling data errors compared with the actual 2004
election).

This week's results:
4% Margin of Error
Obama wins 99.94%, averages 317.3 EV
McCain wins 0.04%, averages 210.7 EV
Electoral tie 0.02%

12.25% Margin of Error
Obama wins 96.6% averages 314.0 EV

McCain wins 3.1%, averages 214.0 EV
Electoral tie 0.3%

The
4% margin of error simulation captures what current polls say, and
Obama is simply ahead by too much in too many places to see how he
wouldn't win in an election held now. He has double-digit leads in
states with 211 electoral votes, while McCain has such a lead in states
with just 83, so while several states in the middle might go either
way, McCain would need to win just about all of the marginally close
states to eke out a win.

The most relevant new polls this week
are almost all breaking in Obama's favor: Obama now leads in Michigan
by 8, continuing a trend in his favor. It's his largest ever lead
there, and is the third straight poll there where Obama has improved
(moving from a 4 point deficit in late May). Early i

Iowa,
Rasmussen now shows Obama ahead by 10 (up from a 4 point lead in Survey
USA's mid June poll, and a 7 point lead in Rasmussen's previous poll in
early June), suggesting this one-time swing state may also be moving
beyond the polling margin of error.

Rasmussen now shows Obama
retaking the lead in Nevada, where he's now up by 2 after traling by 3
in their previous poll in June. Obama lead in February and March, then
trailed regularly, and now he's back in front there.

McCain
still leads in North Carolina, but it may be tightening a little more,
as Survey USA shows him up by 5, and Rassmussen now shows him ahead by
3.

Obama is making more of the Mountain West competitive, as he
now trails by just 4 in South Dakota (following last week's gains in
North Dakota and Montana).

The other new polls are in states
clearly in one column or another, with some movement favoring Obama,
and other movement favoring McCain, but nothing which yet suggests any
of these states may be competitive in November.

The
state-by-state polling data certainly do paint an optimistic picture
for Obama, but these simulations assuredly overstate the likelihood of
his winning. While there hasn't been much movement recently in winning
percentages, McCain was leading Obama in mid-May, which shows that
things can change over time.  We're still  over three months from the
election, and most of the country isn't really paying close attention
yet.

As a point of comparison, political futures sites like www.intrade.com and the Iowa Electronic Markets
currently give the GOP about a 30-35% chance of winning in November,
with the Democrats at about 65%-70%. That's surely more accurate than a
95% or better chance for a Democratic win, but my biased personal
opinion is that Obama's chances are better than the markets say; I'd
guess he has about a 75% chance of winning.