It's time for another in my weekly series of election simulations, using data from Votemaster Andrew Tanenbaum's www.electoral-vote.com.

The standard disclaimers apply: the polling data are still thin, with the most recent poll in some states still being from February; and we're several months away from the election, so things will certainly change.

As I started to do last week, in addition to running a simulation using the 4% margin of error common to most polls, I'm running another simulation with about a 13% margin of error. I've chosen this number by doing a regression against the errors in 2004 polling data compared to the actual election result, as made available from www.electoral-vote.com. This 13% number will slowly decrease to about 10% just before the election in November - the closer we are to the election, the more accurate the polls tended to be in 2004.

This week's numbers, from 10,000 trials:
4% Margin of Error
Obama wins 98.6%, averages 301.1 EV
McCain wins 1.3%, averages 236.9 EV
Electoral tie 0.2%

13% Margin of Error
Obama wins 77.8%, averages 287.6 EV
McCain wins 20.9%, averages 250.4 EV
Electoral tie 1.3%

Obama is enjoying his post-election bounce, and this is his strongest showing yet. He took the lead in Michigan, widened his lead in Wisconsin, and another Rasmussen poll now has him trailing by just 2 in North Carolina. Not all the news for Obama is good: a new poll in Indiana has McCain on top (the previous two polls, from April, agreed on the 8 point margin, but disagreed on the leader, so Tanenbaum and I were calling it a tie).

One interesting tidbit: Obama is just 8 points down in West Virginia now, polling much more strongly in a general election matchup against McCain than he did in the primary against Clinton. This reinforces the fact that losing a primary doesn't inherently mean that you lose the general election (or the opposite). Democrats will still tend to support the nominee, even if their preferred candidate doesn't get the nomination.

The 4% margin of error numbers are, at best, a snapshot summarizing the recent polling, and Obama is now ahead in states which total over 300 electoral votes. Since my model treats each state as an entirely independent election, the only way McCain wins with a small margin of error is by getting lucky in pretty much all close states: Ohio, Missouri, Virginia, and Michigan.

The 13% margin of error allows for more variability, trying to capture possible movement from the electorate changing its mind between now and November. This still assumes each state is an independent trial, though, which isn't ideal: it's more likely that shifts in opinion in one state correlate with shifts in opinion in other states moving in the same direction. But simply increasing the margin of error gives McCain a plausible, if still unlikely, path to victory, as he is given some chance to win states like Pennsylvania, New Jersey, and Oregon.

When I use 4% margin of error, only 13 states didn't always go in one column, and in just 6 of them did the person trailing win at least 5% of the time: North Carolina, Virginia, Missouri, Ohio, Connecticut, and Michigan.

By contrast, with a 13% margin of error, just 8 "states" were always in one column: Obama always won Illinois, Vermont, Hawaii, and D.C., while McCain always won Alabama, Arkansas, Tennessee, and Utah. Each candidate won at least 5% of the time in 26 states.

That Obama's electoral vote averages are lower than the total of the states he currently leads reflects that he's taken small leads in several states, and in the simulations he doesn't always win them. For now McCain has more potentially close pickups than Obama has. But the current polling is certainly good for Obama, and unless McCain can swing opinion back his way, he's headed for defeat.

And Obama's plans to continue the 50-state strategy will put more pressure on McCain, because he'll have to spend in "safe" GOP states to keep them that way. It's beginning to look like a best case for McCain would be to replicate the Bush map against Kerry. That he's running for Bush's third term may be true in more ways than we first thought.