The reason Clinton struggles under seemingly decent conditions is obvious. After one party holds the presidency for two terms, voters want change. In the model, this desire for a new direction manifests itself as a 4-point reduction in the candidate's take of the popular vote compared with what candidates could expect had their party held the White House for just one term.
"One of the regularities you'll find for all presidential elections since World War II is, after a party has been in power eight years and is trying to hold on to the White House for a third consecutive term, it gets harder," Abramowitz says. "Another way of looking at it: In the first election after a party takes over the White House, you have a significant advantage. And the next time, after you've held another term, you lose that advantage."
Campaign operatives love to hate this academic assessment of politics, much like Wall Street belittles the technical analysts who use past performance to predict stock-market moves.
The tension between the strategists and the scientists speaks to the distinct approaches they employ: Political professionals (including journalists) study strategy, tactics, the day-to-day activities of a campaign, while political scientists see fundamentals shaping every election, almost no matter the strength of a candidate.
In 2012, for example, most strategists think Obama won because he ran one of the best presidential campaigns in American history while Mitt Romney ran one of the worst. According to political scientists, however, Obama's victory was a product of favorable conditions, such as an improving economy, decent approval ratings, and his incumbency. The unemployment rate was high, yes, but the state of the economy matters little compared with the direction it's headed.
In an era of hyper-professionalized, financially flush campaigns, it is this set of fundamentals that will make the difference between winning and losing, the scientists argue.
"The notion the campaign doesn't matter, it's not that simple," says Michael Lewis-Beck, a political science professor at the University of Iowa. "It doesn't matter so much because everyone is campaigning so hard that they cancel each other out."
Lewis-Beck showcased his own presidential model—one of many that now dot the political landscape—on the political science blog Monkey Cage. Academics began developing statistics-based predictions as early as the 1970s, but they have become more popular and mainstream since Nate Silver correctly forecast the 2008 and 2012 presidential elections.
In an era of hyper-professionalized, financially flush campaigns, it is this set of fundamentals that will make the difference between winning and losing, the scientists argue.
Silver is a controversial figure in the political science world, where he's seen as a practitioner who went mainstream and came to define the entire forecast-model genre. As Romney supporters can attest, Silver's forecasts have been accurate, but they also depend on polls—many of which are not yet available or are of little use this far from Election Day. This means that Silver's forecasts might not be accurate untila couple of months before an election, and to political scientists who develop models, the goal is not just to be accurate but to be accurate long enough before an election to make a true forecast.