We enjoy believing debates are central determinants of election outcomes.
They give campaigns a focus, journalists a hook around which to wrap their coverage and citizens the illusion that we render verdicts based on intellectual trial by combat.
In truth, though, debates have probably never decided a presidential election.
That does not mean they don’t have an effect — it just isn’t typically a decisive effect.
One reason for their failure is that most presidential elections haven’t been that close. Over half of the elections since 1960 have been decided by margins of more than 4 points.
Those 4 points are relevant because, according to Gallup, that’s the average change in the margin pre- and post-debate.
Of course, Gallup’s aren’t the only polls, and the polls often provide divergent data.
A comprehensive analysis by Professors Robert Erikson and Christopher Wlezien found that “debates seem to make at least a bit of difference,” though “any claims about debate effects … are fragile.”
The Bush-Gore debates of 2000 are one of the two sets of debates Gallup analysts regard as influential. 1960, where data is much thinner, is the other.
But the 2000 data are far from clear.
In a panel study re-interviewing the same individuals before and after the debates, Professors Sunshine Hillygus and Simon Jackman detected a change in the margin of about 4 points in George W. Bush’s direction.
But which voters were most affected? Most were mismatched partisans — i.e., Republicans who had been for Al Gore and Democrats who had favored Bush — a segment that barely exists in today’s political world and who might not have found their way home without the 2000 debates. Those undecided going into the debates split evenly.
Moreover, ABC News polling at the time suggested almost no movement after the second and third debates, with Bush holding the lead before and after both. Pew reported that Gore moved from a 1-point deficit to a tie after the third debate, a difference within the margin of error, to be sure.
Now, winning a debate is not the same as winning an election.
John Kerry bested Bush in three consecutive debates in 2004, but it was Bush who won the race. Ronald Reagan won reelection by a landslide in 1984, despite losing to Walter Mondale in the first debate and essentially tying him in the second.
In 1988, George H.W. Bush won the election by a sizable 7-point margin, despite losing to Michael Dukakis in their debates.
This election could have been different. It’s closer than usual. Various poll aggregators peg Hillary Clinton’s lead at 1.5 to 4 points.
A Donald Trump win at Hofstra could have altered the course of this race. But he lost the debate, badly.
The two public post-debate polls gave the former secretary of State the decision.
The CNN/ORC poll gave Clinton a 35-point margin. In the 20 debates after which they’ve polled, only one yielded a larger margin for the winner — Mitt Romney’s pyrrhic victory over President Obama in their first encounter in 2012.
Perhaps more important, the poll suggests Clinton won among noncollege-educated whites, a core of Trump’s base and a segment with which she has been struggling.
She garnered almost unanimous acclamation from Democrats, while only 55 percent of Republicans thought Trump did the better job.
Public Policy Polling’s post-debate poll reveals some methodological issues, which we’ll discuss in the future, but it gave Clinton a less spectacular, though still substantial, 11-point victory.
If anything, this debate solidified Clinton supporters while creating further doubts among Trump supporters and undecideds.
It probably won’t change the election’s outcome, but it could have, in Trump’s favor.
Instead of making the most of the opportunity, he squandered it by failing to prepare, through his off-putting body language, by vividly displaying his foul temperament and by focusing on himself rather than on the voters, whereas Clinton was excellent on almost every level.
Mellman is president of The Mellman Group and has worked for Democratic candidates and causes since 1982. Current clients include the minority leader of the Senate and the Democratic whip in the House.