Do political campaign debates matter?
Absolutely, and the first such case is Abraham Lincoln Vs. Stephen Douglas in the Illinois Senate race of 1858, which helped elevate Lincoln to the Presidency, although losing the Senate seat due to the Democrats controlling the state legislature, and choosing incumbent Democrat Douglas for the new term of office.
Since Presidential debates came about in 1960, and then revived starting in 1976, there have been moments when they really mattered, even if often boring, including:
1960–Richard Nixon sweating and looking tense, while John F. Kennedy smiled, looked tanned, was relaxed.
1976–Gerald Ford says Poland is a free nation, which helps to elect Jimmy Carter in close race.
1980–Ronald Reagan talks about the “Misery Index” and says “Are you better off than you were four years ago?”, and defeats Jimmy Carter.
1984—Ronald Reagan says he will not use age as an issue to show the “youth and inexperience” of opponent Walter Mondale, who he defeats.
1988—Vice Presidential nominee Lloyd Bentsen tells opponent Dan Quayle that he is not another John F. Kennedy, and sets the image of Quayle for all time as an incompetent Vice President, and have no chance to be President when he decides to run in 1996.
1992—George H. W. Bush looks constantly at his watch, during the debate with Bill Clinton, who defeats him, and also Ross Perot.
2000–Al Gore walks over to George W. Bush as he answers question, comes across as a weird action, and also breathes deeply at Bush responses, making Gore seem haughty and condescending.
2008—Sarah Palin does an embarrassing performance in Vice Presidential debate with Joe Biden, harms John McCain campaign.
2012–In Republican Presidential candidate debates, Rick Perry cannot remember the three agencies of government he wishes to eliminate, which ends his candidacy.
2012—Joe Biden laughs at Paul Ryan statements in Vice Presidential debate, weakens Ryan image as Mitt Romney’s running mate.
Also, political campaign debates draw attention to the race, and there will be many Presidential debates starting tonight for the Republicans, and in October for the Democrats.