As the summer wanes and the presidential campaign continues, a recurring question relates to electoral mathematics – what states will either President Obama or Governor Romney need to win in November? There are several that are touted as battleground states that will determine the outcome of the election. Is this true?
As any follower of presidential elections already knows, it requires 270 electoral votes to win a presidential election.
Running the current statewide polling data through our simulation model, there are currently sixteen states – including Pennsylvania – in which Obama has a greater than 95% probability of winning. These sixteen contribute a total of 205 electoral votes to his total. Governor Romney also has sixteen states in his certain win column, but because of population differences they contribute only 141 electoral votes to his total.
A second level includes those states that while not certain wins for each of the candidates a win is considered likely. This level adds three more states to the Obama tally with an additional 58 electoral votes. Romney gains a single state and only three additional electors.
Including this level the President currently has 263 electoral votes requiring only seven additional electors. Governor Romney has 144 electoral votes and still needs 126 more.
To reach 270 it might be possible for Romney to win all four of the states that are leaning in his favor – Kansas, Kentucky, South Carolina, and South Dakota. This adds thirty-two electors to his total. If he also takes all three of the true tossup states – Colorado, Missouri, and Tennessee – he gains an additional thirty electors. But that only brings him to 203 – still 67 short. To make up these additional votes he will need to take all of the states that are polling close, but still leaning Obama.
At this point the probability of an Obama reelection is at 99.8% – as close to a certainty as one might expect. But it might be possible for Romney to change the result by swaying a few of the battlegrounds. But it will take more than a single win. For example Ohio is currently a likely Obama win. But if between now and November Romney can change that outcome and take Ohio his odds barely improve with Obama’s chance of winning dropping to just under 99%.
Instead, Romney will have to sweep all of the battlegrounds. Assume that he is able to win Florida, North Carolina, Ohio, and Virginia. His probability of winning puts him back into play at 46% to the President’s 52% with a 3% chance of tie. If you add Michigan or Pennsylvania into the Romney win column his chances rise to a likely – albeit not certain – electoral college win. Of course it is important to recognize that these are all states in which Obama is currently leading, some – such as Michigan and Pennsylvania – by significant margins.
This is not to imply that the election is over; far from it. This is simply a snapshot based on the current statewide opinion polls. It remains to be seen how Romney’s choice of Paul Ryan will play out in the polls or what impact the party conventions will have. As we enter the fall campaign season we are sure to see changes in the numbers. But based on the current polls, the odds are not on a photo finish, but instead a contender who is struggling to get out of the gate.