By Helmut Norpoth
Labor Day marks the unofficial end of summer and, in presidential election years, the traditional beginning of the general election campaign. At this juncture Nate Silver’s popular website, FiveThirtyEight, has all but anointed Democrat Hillary Clinton as the inevitable winner over Republican Donald Trump in November. The 538 forecast based on an aggregation of polls gives Clinton a 70 percent chance, give or take a point, to defeat Trump. It is a victory not only in the popular vote but also in the Electoral College. The polling averages produced by RealClearPolitics and The Huffington Post agree. They all have shown a Clinton lead for months, punctured only briefly when Trump clinched the GOP nomination in primaries or won it at the Republican National Convention. Polls are shining a bright light on Clinton’s prospects while casting a dark shadow on Trump’s. So it seems. How serious should we take these poll-driven forecasts?
By now we have lived with scientific polls in American presidential elections for 80 years. It started in 1936, when George Gallup conducted the first poll of a representative sample of American voters. For the record, he got it right that year. Few readers may be old enough to remember. Franklin Roosevelt was running in 1936 against … quick, who was the Republican opponent? OK, it was Alf Landon of Kansas. FDR led him in every poll conducted by Gallup and won in one of the biggest landslides — a great start. Gallup would not always be so lucky. In 1948, his polling consistently showed Republican Tom Dewey defeating Democrat Harry Truman, the incumbent president, who wound up with the victory on Election Day.
Back to Labor Day. At this point during the 2008 election cycle, Republican John McCain was ahead of Democrat Barack Obama 49 percent to 44 percent in the Gallup poll. Many probably don’t remember it. McCain’s lead was famously trumpeted as a “game change,” triggered by his choice of Sarah Palin as his running mate. The strong showing of the GOP ticket in the polls raised the hopes of the McCain camp for a victory in the November, while unnerving the Obama camp. Then the economy took a sudden nosedive as Lehman Brothers collapsed and Wall Street crashed. As the candidate of the White House party, on whose watch this calamity occurred, McCain saw his fortunes tank in the polls. It also did not help that Palin, his vice-presidential candidate, came across as clueless and tongue-tied on television in interviews with Charlie Gibson and Katie Couric. So, real-life events unfavorable to the White House party and missteps in the election campaign combined to reverse a lead in the polls that one side, McCain in this case, enjoyed at the beginning of the general election campaign. Lesson: Beware of pollsters bearing election forecasts eight weeks before Election Day.
Helmut Norpoth is a political science professor at Stony Brook University and has designed models to forecast elections in the U.S. and abroad. He will be contributing ongoing election analysis ahead of the 2016 election.