BEGINNING Sept 29, a series of three debates between presidential candidates Joe Biden and Donald Trump (and a single debate between vice-presidential rivals Kamala Harris and Mike Pence) will lead to the climax of this year’s US election on Nov 3. As always, the debates will draw huge television audiences and provide endless speculation before and after the contests about expectations, performances, and, sometimes, the effects of gaffes or misstatements by the performers. But will these exciting match-ups make a difference where it counts, in the ballots cast by voters? If history is our guide, the answer is: probably not.

The debates are thrilling the way heavyweight prize fights are. Spectators cheer for their favourites, and dream about knockout punches. However, just as those spectators don’t change their loyalties during or after the fights, neither do many debate-watchers change or make up their minds about presidential candidates–regardless of who wins.

In 1858, Abraham Lincoln and his rival for a US Senate seat, Stephen Douglas, engaged in a series of seven debates, one in each Illinois congressional district. The debates were engaging and excited the public. At that time, US senators were selected by each state’s legislature, and in the end the legislators chose Douglas. This was the last election Douglas would win, and the last one Lincoln would lose, as it elevated his personal and political profile, positioning him for the all-important 1860 presidential election, from which he emerged victorious to abolish slavery and save the union. In that pre-television era, those debates were very important.

In 1960, the American public was excited about an election featuring two young, ambitious politicians: Vice-President Richard Nixon, 47, and Senator John F. Kennedy, 43. Both men were seasoned debaters, so they happily agreed to a series of four televised debates. This thrilled the American people, as evidenced by the level of viewership: seventy million people – two-thirds of the nation’s adult population – watched or listened to the first debate.

Polls following that first encounter revealed that a majority of those who listened to the debate thought Nixon won, while those who watched it (a much larger audience) felt Kennedy had prevailed. Why the difference? Most analysts and historians believe it was because of the candidates’ respective appearances. While Kennedy looked bronze, calm and confident, Nixon, though in command of the issues and facts, looked tense and perhaps even angry. Also, Kennedy’s clean-shaven look contrasted with a “five o’clock shadow” on the dark-haired Nixon, who, prior to the debate, declined an offer by a network technician to have make-up applied to his face.

To this day, it’s the only one of the Nixon-Kennedy debates that historians and teachers discuss when explaining how, from that campaign, the nation learned the importance of appearance and the power of television.

In the years following the Kennedy-Nixon debates, presidential campaign front-runners worried that a bad debate appearance could hurt their chances, so they declined to debate, even when challenged openly. Indeed, President Lyndon Johnson, though very popular in 1964, refused to debate Barry Goldwater that year, and Nixon declined debates with his opponents in 1968 and 1972, Hubert Humphrey and George McGovern. At that point, it looked like televised debates might never become the norm in American presidential campaigns.

But things changed in 1976. The incumbent, Gerald Ford, had not been elected on his own, but instead was appointed vice-president by Nixon and, when Nixon resigned, ascended to the top job. Democrat Jimmy Carter was a true outsider, having never served a day in Washington. Consequently, both candidates seemed uneasy about their standing with the public, so both agreed to a series of debates. This would prove extremely important for the future of presidential debates, which have been held in every election since.

There have been many significant mistakes, and a number of catchy or funny one-liners, since the debates were renewed. In the 1976 debate on international policy, Ford mistakenly asserted that Poland, a Soviet puppet state at the time, was not dominated by its puppeteer. But Ford recovered from his flub and came within inches of pulling an upset that November.

In 1984, President Ronald Reagan, appearing tired and confused, stumbled badly in his first debate against Democrat Walter Mondale. This ignited long-held concerns that Reagan, then 73, was too old for the job. But Reagan made a memorable comeback in the next debate. When asked about his age, he replied: “I want you to know that I will not make age an issue of this campaign. I am not going to exploit, for political purposes, my opponent’s youth and inexperience.” Mondale was 56 and had served as vice-president. It was a line that made everyone, including Mondale, laugh – and largely put to rest worries about the president’s age.

Notwithstanding these and other interesting occurrences, seldom has a debate gaffe, or memorable line, made a difference in the election that followed. Nor has winning a debate, or a series of debates, mattered much. For instance, in 2004 the incumbent, George W. Bush, debated John Kerry three times, and Kerry won all three debates, according to the polls. But Bush still won by the small margin by which he’d been expected to win. And in 2016, Hillary Clinton defeated Trump in all three of their debates, but – despite of winning the popular vote – lost the election.

So have televised debates ever proven decisive in a presidential race? Perhaps, twice. The first time was when Kennedy defeated Nixon. In their three subsequent debates Nixon did very well, and wore the make-up he’d refused in the first contest. But millions more people watched the first than any of the follow-up debates that year, and Nixon lost by the closest popular margin in modern history.

The other year a debate might have made the difference was 1980. In their single head-to-head debate that year, President Carter and challenger Reagan fought to a draw, basically – until it was time for their closing remarks, when Reagan famously asked the television audience: “Are you better off now than you were four years ago?” The question resonated at the time because inflation and unemployment were very high – higher, that is, than four years earlier.

Reagan went on to win a landslide, carrying 44 out of 50 states, in an election most analysts expected to be close. Whether he would have won without the debate is, of course, debatable.

Perhaps in the final analysis, even if debates aren’t election game changers, they can be important and informative. Moreover, when people cast their votes, they’re guided by things bigger than 90-minute debates – things like candidates’ records, actions, and proven character. So debates are worth watching, even if they don’t make or break a candidate’s chance to win.

William G. Borges is a professor at HELP University.