They helped affirm the importance of television in American politics, making John F. Kennedy a star. They showed the political passion of Ronald Reagan, making the question of whether you are better off than you were four years ago one of the standard measures of American life. They demonstrated the importance of body language in the body politic, assuring that no exasperated presidential candidate ever would follow George H.W. Bush’s example and look at his watch in the middle of an exchange with another candidate.

The presidential debates get under way Friday, September 26, beginning the last phase of a campaign that has seemed to span a lifetime — starting months ago when Hillary Clinton seemed invincible, John Edwards seemed faithful, John McCain seemed hopeless, and Barack Obama seemed to be overreaching. These forums are a modern addition to the campaign process — no candidates engaged in a debate before the Kennedy-Richard Nixon encounter exactly 48 years before this week’s session — and they often have provided important, defining political moments.

The upcoming debate at the University of Mississippi should be no different. The Republicans hope to put Mr. Obama’s youthfulness and inexperience on display. The Democrats hope to put Mr. McCain’s age and ties to the George W. Bush White House on display. Neither is likely to succeed. If previous debates tell us anything, it is that the unanticipated insight — the spontaneous, telling moment — is what becomes a potent factor in the general election and a memorable touchstone in American political history.

Today, for example, nobody remembers anything about Quemoy and Matsu, particularly which candidate (Nixon) charged the other (Kennedy) with reluctance to defend these two islands in the Taiwan Strait. But everybody “knows” Kennedy won the first debate — even though the people who listened on radio and didn’t see the contrast between the crisp-looking senator from Massachusetts in the blue suit and the perspiring vice president from California in the gray suit reached the opposite conclusion.

Even the people sitting on the set, viewing the debate in color rather than in black and white, didn’t “know” that Nixon lost. “We could not see the debate through television,” the former NBC newsman and the only person from that first debate who is still alive, Sander Vanocur, recalled in a telephone interview the other day. “We saw only with our natural eyes. And looking with the naked eye at a gray suit with a gray background didn’t seem so terrible in person.”

This time there will be certain questions each side will want to have asked — and certain points each side will try to make, even if it requires ignoring the questions. Watch for that, by the way. It’s the oldest trick in the (nearly half-century old) book.

Here are some questions that you may join me in hoping are asked:

Which advertisements that have come out of your camp would you most resent had you been the target of them? Please do not deliver a sermon on clean campaigning, and do not use this as an excuse to badger your opponent. Instead, please provide a simple answer to this specific question.

Dream on if you expect an answer to this, though they both ought to be ashamed of themselves.

Senator Obama has very little conventional experience, and Governor Palin has very little conventional experience. Does the fact that each side has a compelling but conventionally inexperienced candidate stand as testimony of the relative unimportance of this issue? Please do not use this question as an opportunity to defend the record of any single individual on these two tickets.

Dream on if you expect an honest answer to this question, and if we do get a candid response, you can expect it to include the two words “Abraham Lincoln,” which pretty much should end the discussion.

The details of many of your proposals — especially on taxes and medical insurance — are important as glimpses into how you think and the role you feel is appropriate for government in a free-market economy. But don’t you agree that nit-picking each other’s specifics is not only a waste of time but also fundamentally dishonest, because it is not you but members of Congress who will ultimately shape legislation in these areas?

Dream on … well, you know the rest of the sentence. Neither of these men is a particularly effective lawmaker, which is no sin. Kennedy and Nixon weren’t, either, and the only accomplished legislator of the 20th century to sit in the White House, Lyndon B. Johnson, wasn’t so much a lawmaker as a deal-maker. What we really need to know is how both of them will deal with Congress and what Congress wants, not how they would deal with the aides they appoint to draw up the legislation they want.

Is the country — to borrow the best line from any presidential debate ever — safer today than it was four years ago?

This is not a question about dreams but one that invites nightmares. The country has been blessed since September 11, 2001 — a sentence every columnist resists typing for fear that he, like a fan who talks aloud about a no-hitter, might be shown, tragically, to be counting his security chickens while plots are being hatched. But it is not unreasonable to ask whether these two presidential contenders think the Bush administration has done a good job, has done enough, has not done enough but been lucky, has set us on a path to complacency, has set us on a path to safety, or has set us on a path to disaster.

You may not get the answers to these questions. You may not even get these questions. But you almost certainly will get what the candidates do best — an answer to a question that wasn’t asked. If we’re lucky, that question might be: How do these candidates measure up to the challenges we face?

© 2008 The Pittsburgh Post-Gazette