The intensity of the initial skirmishes in the campaign between President Barack Obama and Mitt Romney underscores a new reality about presidential politics: What happens in the months before Labor Day and the candidates' debates in the fall will shape the race and, if history is a guide, determine who wins in November.
The next 60 to 90 days may be among the most important of the general election. The Obama and Romney campaign teams will try to define the opponent as negatively as possible. Both sides will put in place the money and machinery needed to spread their messages and turn out their voters on Election Day. Mistakes will be costly.
What used to be seen as a transitional period between the nomination season and the general election campaign has disappeared, leaving little margin for error. That is particularly true for the challenger and his team, who are coming off a long primary fight that has left them exhausted and their resources depleted.
"There's no such thing as a fall campaign anymore," said Steve Schmidt, who was the chief strategist for Republican Sen. John McCain's 2008 general election campaign. "Once the nomination is sewn up, a presidential campaign is a continuous enterprise. The fall campaign is fundamentally about executing on the platform you build over the spring and summer. Wasted time is hard to make up."
Labor Day was once seen as the official kickoff to the general election, a characterization that seems quaint in this era of round-the-clock politics and hypercommunications. In fact, early September may be the moment that signals to the country which candidate is likely to win.
It is overwhelmingly the case that the candidate who has led just after Labor Day has gone on to win the election. Because the conventions are now held around Labor Day, rather than much earlier, the first polls taken after the candidates' postconvention bounces have dissipated will be key indicators of how the race will go.
Among the exceptions: Ronald Reagan trailed Jimmy Carter in a mid-September 1980 Gallup poll and went on to win an electoral landslide. Al Gore led George W. Bush narrowly in an early September 2000 Gallup survey. He won the popular vote, but not the presidency.
But in nearly every other case dating to 1952, the leader in the Gallup Poll around Labor Day went on to win.
Four years ago, McCain led Obama briefly in mid-September, but that was more a reflection of the boost he got from his convention.
Those polls were an anomaly in a campaign in which Obama always appeared in control.
Through much of July and August that year, McCain's campaign team feared that the election was already lost.