THE UNKNOWN UNKNOWN
There's a reason we call the "October surprise" what we do -- sometimes (though admittedly not often) we simply don't know what will tilt the results of a race until Election Day is upon us. The term "October surprise" dates to 1972, when National Security Advisor Henry Kissinger declared less than two weeks before the presidential election that peace was "at hand" in Vietnam -- comments that were credited with helping President Richard Nixon resoundingly defeat George McGovern (though in truth, Nixon didn't need much help). During the 1980 election, Ronald Reagan's campaign worried that President Jimmy Carter would strike an eleventh-hour deal to free American hostages in Iran (instead, they were released shortly after Reagan was sworn in as president). In 2004, John Kerry blamed his loss to George W. Bush on a video released by Osama bin Laden just days before the vote ("We were rising in the polls up until the last day when the tape appeared," the Massachusetts senator lamented).
In others words, we have a ways to go until November, and anything from security in Afghanistan to violence in Syria to elections in Venezuela (ominously scheduled for October) could emerge as a potential game-changer. When the 2008 presidential election got underway, everyone assumed that foreign policy -- specifically the war in Iraq -- would be the dominant issue in the campaign. And then the global financial crisis hit, propelling the economy to the top of the agenda. It's too early to rule out the reverse happening in 2012.