Mellman: Do debates matter?

You’ve already witnessed Tuesday night’s debate. Writing during the day Tuesday, I haven’t.

But I’ll bet you’ve also been showered with commentary suggesting it could “rattle the race,” “shake up the standings,” or change the course of the election, and of history.

We love the illusion that the skills on display in debates somehow map onto the requirements of the presidency; and that we render political verdicts based on what appears to be intellectual trial by combat.

Don’t bet on it.

In reality, debates have probably never decided a presidential election.

Michael Dukakis, Al Gore, John Kerry and Hillary Clinton all “won” their debates, but none won the White House.

That does not mean debates have no effect — effects are just usually small and not decisive.

1960 is often trotted out as the iconic example of a debate that changed history, but the data is thin at best.

John F. Kennedy had already been gaining going into his first debate with Richard Nixon, tailing by a single point. After all the debates, Kennedy led by 4 points in a race he eventually won by less than 1 — well within the margin of error of the pre-debate poll and certainly closer to that survey than to the post-debate poll.

The data are just not sufficient to adjudicate whether the debates made a difference, let alone a decisive difference, for Kennedy.

In 1988, George H.W. Bush won the election by a sizable 7-point margin, although he lost the debates to Michael Dukakis.

John Kerry bested Bush’s son in three consecutive debates in 2004, but it was Bush who won the race.

Some argue debates were decisive in 2000, but the data are murky here too.

One panel study, re-interviewing the same individuals before and after the debates, suggested a 4-point pick up for George W. Bush.

However, 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 well within the margin of error.

Hillary Clinton’s confrontations with Donald Trump in 2016 are more difficult to disentangle, in part because other events, like the “Access Hollywood” tape, hit the airwaves at a similar point in time, making it impossible to isolate the debate’s impact.

Trump’s lies notwithstanding, there’s no doubt voters gave the debate victory to Clinton in all three of their encounters, by margins ranging from five to 40 points.

But what effect did debate victories have on the horse race?

Going into the debates, Clinton led by an average of 2.3 points. After the debates, and after “Access Hollywood” and a variety of other Trump revelations, Clinton’s lead averaged about 4.75 points — a small, but potentially important gain of about 2 1/2 points.

However, Clinton’s 2.3-point edge going into the debates proved closer to her ultimate margin of victory in the popular vote (2.1-points) than her post-debate advantage.

In short, in 2016 too, it’s hard to argue a major impact from debates.

Of course, the conclusion of this brief stroll through debates past can say nothing about unusual debates, outside the realm of historical experience.

For example, a greater impact might ensue if a candidate drooled into the camera for 20 minutes or walked off the stage mid-debate, angered by moderators’ questions. Donald Trump is perfectly capable of these and other bizarre behaviors, far from the norm in these events.

But to change the dynamic of this election, it’s Biden who must perform in a uniquely negative way.

You know whether that transpired. But it’s not likely to have happened in the first debate, or in any of those to come.

And so, we are likely once more witnessing an intensely interesting, much-hyped national political spectacle that will exert little real impact on the outcome of the election.

Mellman is president of The Mellman Group and has helped elect 30 U.S. senators, 12 governors and dozens of House members. Mellman served as pollster to Senate Democratic leaders for over 20 years, as president of the American Association of Political Consultants, and is president of Democratic Majority for Israel.