Washington — It's the ultimate television event. The presidential debate. High drama. Excitement. Tremendous stakes. History in the making right before America's eyes.
When Ronald Reagan and Walter Mondale step before the cameras on Sunday (9 p.m., EDT), an estimated 75 million Americans - including most of those who will vote on election day - will be watching. The TV audience will be 7,000 times greater than the huge crowd that assembled 126 years ago to hear the first of the historic Lincoln-Douglas debates in Illinois. The emphasis in the Reagan and Mondale camps will be on TV strategy.
Although hundreds of guests will crowd into Louisville's Kentucky Center for the Arts to witness the debate firsthand, they will serve only as a stage-prop in this television spectacular. What's important to Mr. Reagan and Mr. Mondale will be the images that flicker across the millions of TV tubes linking them with the nation.
Several days before Sunday's debate, each candidate slowed down his schedule, began getting more rest, and started shaping his tactics.
President Reagan, according to aides, plans to view a 40-minute videotape of Mondale. Reagan wants to watch Mondale's reaction under fire, and study Mondale's various methods of attack. Practice debate sessions will include David A. Stockman, director of the Office of Management and Budget, playing the role of Mondale.
Over at the Mondale campaign, the same sort of planning goes on. Aides are using mock debates between the candidate and Michael Sovern, the president of Columbia University, to hone Mondale's tactics. The mock debates are videotaped, and aides then review them to suggest improvements.
Sunday's debate is the World Series and the Super Bowl for Mondale. He's down about 20 points in the polls. A Thursday poll by USA Today puts Reagan 25 points ahead. On debate day, less than a month will remain until election day.
Mondale enthusiasts continue to hope. They recall that this isn't the first time Mondale has been far, far behind.
Earlier this year, after Gary Hart ran away with the New Hampshire primary, Mondale's chances looked as bleak as a Minnesota blizzard. But the challenge seemed to energize Mondale. His speeches became tougher. Some aides talked of withdrawing from the race; but he cheered them up and predicted victory. Then, in what now appears to have been a turning point, he threw Senator Hart off his stride with sharp attacks during the March debate in Atlanta.
Aides look for that kind of turnaround now. They say Mondale will go into Sunday's showdown trying to do several things:
* Show that he, not Reagan, is more concerned about middle-income families, while Reagan pampers the rich.
* Show that he has a plan for the future on issues like the deficit and arms control, while Reagan doesn't.
* Raise concerns about Reagan's second term, emphasizing social security, medicare, and the environment.
* Point to Reagan's effort to cozy up to the ''right wing'' by favoring laws (on such things as abortion) that would intrude into private lives.
The format for the debate was dictated mostly by the Reagan White House. Mondale would have preferred a more free-wheeling debate, with each candidate able to ask questions of the other. Questions will come from a panel of reporters. Candidates will have 21/2 minutes to answer each question, with 1 minute of rebuttal from each. The 90-minute debate is expected to include, at most, only 10 questions.
The first debate will be on domestic issues. The second on Oct. 21 in Kansas City, will deal with foreign policy. There are indications that Mondale will try to find avenues during Sunday's debate to bring up foreign policy questions, such as the recent US Embassy bombing in Beirut. Aides feel that Mondale must find ways to break through what they call Reagan's ''question-free zone'' on issues like Beirut if the Democratic ticket is to have any chance.
Next week's debate, of course, will be a far cry from the first, three-hour encounter between Abraham Lincoln and Stephen A. Douglas. There were no cameras then, no microphones. Just a platform and the blazing sun overhead. When it was over, rambunctious supporters of Lincoln hoisted him on their shoulders and carried him victoriously from the scene.