We've reached the point of the campaign season when everyone gets obsessed with electoral maps, rearranging states to see all the different ways that Barack Obama or Mitt Romney can win. But let me save you some time: the conventional wisdom holds that there are just nine states that might go either way on Nov. 6, meaning that if the other 41 states go the way they're supposed to, there are exactly (and only) 512 possible outcomes. I've calculated the electoral vote tally for all 512 combinations and Obama wins re-election in 84.2 percent of them.
Before we move on, let's discuss the distinction between odds and predictions. If you flip a coin, the odds are 50 percent that it will land on either side. If you call heads or tails, you are making a prediction. Anyone who's ever lost a hand of poker after starting out with a pair of aces knows, painfully, the difference between odds and predictions. So, these electoral map odds are not about making a prediction of who will win — that's the job of people like Nate Silver. But for the last three presidential election cycles, I've found charting out the electoral vote odds a useful way to cut through the clutter of overheated punditry and keep perspective on the state of play in an election.
While most of the campaign coverage is dominated by familiar cliches of the race being too close to call, nail-biting, and down-to-the-wire, there is arguably a lot more known about the Nov. 6 vote than there is unknown. According to the Constitution, the presidential election is actually 51 separate races. Each of those races is a winner-takes-all contest for a certain number of votes in the Electoral College. (Note: My Atlantic colleague Chris Heller points out this is not entirely correct since Nebraska and Maine award some of their electoral votes proportionally. For the purpose of this math, I assumed those states are winner-take-all.) The presidential candidate who gets 270 or more electoral votes will be the next President. We know the outcome of the vast majority of those 51 contests: New York, California, and Hawaii, and so on, will award their electoral votes to Obama, while Wyoming, Oklahoma, Utah, etc., will award their electoral votes to Romney. In these 41 "known" races, Obama has a huge lead over Romney: 237 electoral votes to 191. Here they are mapped courtesy of 270towin.com.
In the nine remaining toss-up states — Nevada, Colorado, Iowa, Wisconsin, Ohio, New Hampshire, Virginia, North Carolina, and Florida — there are 110 electoral votes up for grabs, but because Obama needs only 33 of those votes to win re-election, he wins in the vast majority of the possible scenarios. As a mathematical exercise, Romney has just 76 paths to victory out of the 512 possible combinations.
Here is a spreadsheet with all of the scenarios.
The first time I engaged in this amateur spreadsheet geekery was in 2004 when I was living in Los Angeles and playing a lot of poker (badly, which may warn you away from putting too much faith in my math). A key part of basic poker strategy is knowing at any given time the number of cards remaining in the deck that could help your hand. The idea is to separate the cards you've seen (the ones in your hand and those face-up on the table) from the ones you haven't (those in other people's hand and those still in the deck) and then calculate your odds of getting one of those helping cards. In Texas Hold'em, if you're dealt two aces, the chances of seeing another ace after the flop is the number of aces you weren't dealt (two) divided by the number of cards you haven't seen (47), or 4.26 percent.
Shortly before the 2004 election — which, at least while it was underway, was deemed a close contest between George W. Bush and John Kerry — I realized that you could look at the Electoral College in a similar way as a poker player looks at his hand: you had known states and unknown states, and if you concentrated on all of the possible outcomes rather than trying to predict whether the next card dealt would be an ace or a two, you could calculate odds.
Going into election night 2004, I took the nine states that were popularly considered up for grabs — Michigan, Minnesota, Ohio, Pennsylvania, Wisconsin, Florida, Iowa, New Mexico, and Nevada— and assumed the others would go the same way they did in 2000. (My "safe" states were all correct, except for New Hampshire whose four electoral votes switched from Bush to Kerry.) That meant there were 512 possible electoral vote scenarios and, because so many of the up for grabs electoral votes were in states that Gore won in 2000 (Kerry was defending 70 of Gore's precious electoral votes, while Bush had to defend just 52 he had previously won in order to be reelected), my odds showed Bush was a 70 percent favorite to win reelection, with 358 scenarios in which he won compared to Kerry's 143. (Had I added New Hampshire to my odds charts, Bush would have still won in 67 percent of the possible outcomes.) You could focus on the narrow chances Kerry had to win in 2004 — that is, he would have been President if just 59,388 Ohio votes switched from Bush to Kerry — but going into election night, it would have been one of the unlikeliest outcomes. Anyone who's lost on a bad beat in poker knows it's possible for someone to pull a fourth jack on the river against your flush, but it's not a good bet.
In 2008, the odds shifted strongly in the Democrats' favor, largely because, whether through the charms of Barack Obama, demographic changes in the intervening four years, the worst financial panic since the Great Depression, or an inept McCain campaign, there were more states that had previously voted Republican that were in play for the Democrats. In addition to the nine states that were up for grabs in 2004 there was also a plausible case that Obama could repeat Kerry's victory in New Hampshire and pick up two states that had voted for Bush in the two prior elections, Colorado and Virginia. With those 11 states in play, my odds chart showed Obama winning 77 percent of the 2,048 possible electoral vote scenarios. As it turned out, I was too conservative in estimating Obama's odds, as he won ten of those states as well as the electoral votes from places no one thought were in play: Indiana, North Carolina and the 2nd District of Nebraska.
At a cocktail party a few years back, I described my odds chart to Silver, who goodnaturedly scoffed at its lack of sophistication. He's right, of course: He and other stat-savvy data-crunchers are interested in predicting, as precisely as possible, how people will vote. I come from the other direction: I assume I can't know how the vote will turn out, so it's better to look at the entire universe of possible outcomes. And in this election, the math says Romney has lots of ways to win. Just not nearly as many as Obama.