In these days of October, the living rooms and backyards of suburban Maryland are resounding with a presidental debate that has very little to do with the media fantasia of slick commercials and nightly news reports. Here, among the ranks of undecided voters who comprise the balance of this precarious election, the debate is for the most part a very private one among family and friends.

For John Doskicz, an undecided blue-collar Democrat in Hyattsville, part of the debate was enacted last Saturday, when a neighbor dropped by in an effort to explain why Ronald Reagan should be elected. "Okay, why?" said Doskicz, and for the next 20 minutes he listened to a message that may not have been professional, and probably wasn't all that accurate, but it just might have been something he would remember when the time comes for him to make up his mind.

Doskicz and his fellow undecided voters across the country account for as much as 40 percent of the electorate, according to some polls. As a testament of their unprecedented importance, these still-to-be-convinced voters are the target of a new set of campaign ads being run by the Carter, Reagan and Anderson camps. Several undecided voters in the Maryland suburbs, who agreed to be interviewed as they struggled with their options and tried to make sense out of all they were seeing and hearing, let reporters sit in last week on some of their private debates.

All but one of the dozen voters being followed remain undecided; that one, Greta Reynolds of Olney, says she has chosen Carter over Reagan. For most of the rest, personal contact, even when it is random, has become more important than the buzz of the candidates' carefully-crafted appeals.

In fact, one discussion at home can negate a whole week of news, as in the case of Charles and Dianne Betsey, who reinforced each other's distrust of several major political reports that declared Anderson's campaign virtually dead. For Doskicz, the contacts provided a welcome sounding board for his own views, which are confirmed each time he restates them to another listener.

For Elizabeth Wright, whose politics are sharply at odds with her husband's, the dinner table conversation can subtly recast the issues she had defined before her husband got home. When she talks in private with a visitor at her Gaithersburg home, Wright expresses serious concerns about Jimmy Carter's competence. But when she talks with her husband, Warren Wright, a Reagan supporter who firmly holds Carter responsible for the nation's domestic and international woes, Elizabeth Wright finds herself rushing to Carter's defense -- even on some of the same issues that she finds most troubling.

For her, as an undecided voter leaning toward Carter but still interested in John Anderson, this dialectic probably helps Carter's side at least as much as the barrage of news reports and electronic ads targeted at voters like her in the closing weeks of the 1980 campaign.

"I guess I have to resign myself: My polictical role in life is to cancel out Warren's vote in every presidential election," she says with a soft laugh. o

When she and Warren talk, they inadvertently take parts in a sociodrama. To her, he becomes the voice of Reagan -- a candidate she finds "terrifying," a "hawk," who has the wrong domestic priorities. When Warren takes a stand against Carter, she hears Reagan talking in the background. Suddenly Carter doesn't sound so bad.

Take, for example, the hostage crisis in Iran. Elizabeth, 29, a self-described moderate with liberal tendencies, a confirmed pacifist, a schoolteacher and mother of two, says this in private:

"This issue really has me involved. I'm so glad Carter didn't go in there with both barrels pointed. But at the same time, our hostages aren't home yet. He's a nice guy, but he's not getting us through this. Maybe he's the one we should blame."

Enter Warren, also 29, a lanky contractor who takes a hard line on Iran. "We'd be better off if we had a heavier-handed foreign policy," he says over dinner."It's not a bad idea for foreign leaders to worry about what out president will do if they pull a cockeyed stunt like taking Americans hostage. pJimmy Carter is just too wishy-washy."

Elizabeth, over the moderate, puts down her soda with a mildly perturbed thud. "Warren," she says, "you're coming off as such a hardliner . . . I don't know that being wishy-washy, so called, might not just be part of being a moderate. I'd much rather go to the middle than to either extreme."

At least for the moment, her ambivalende toward Carter on the Iran crisis is resolved.

The funny part of this dynamic, she says, is that, just as she isn't all that sold on Carter, Warren isn't really all that conservative. He voted for George Bush in the Maryland primary and conceded that Reagan is a "little more hawkish than I's like to see."

John Doskicz spends his weekends around his one-room electronics shop in Hyattsville, where business comes largely from the kind of long-time customers who will stop by for a wire and stay the afternoon. One by one, they'll collect on stools tucked between stacks of antennas and cords, or outside around a CB that Doskicz is disassembling, and join an informal club that has a sort of unspoken agenda: hobby-talk, sports, and this month, politics.

Invariably, it is Doskicz, his arms waving and his voice screeching even from beneath a two-ton van, who takes charge. And a comment -- is likely to provoke a long analysis from Doskicz, even though this year, his own feelings remain unresolved.

"I like to take what people say and tear it apart and analyze it," Doskicz says. "And if you do that, if you think it through, you realize what is really going on."

Doskicz decides by critiquing the decisions of others. And so when George Bradburn, a neighbor and president of the Green Meadows Citizen Association, came by the other day to talk about Reagan, he didn't get far before Doskicz began to methodically unscrew his argument.

"Well," said Bradburn a heavy-set middle-aged man who paced the driveway puffing a cigarette with the effort of concentration, "I'm a registered Democrat, as you know. But this year, the Democrat Carter is no good, they couldn't find anyone better to replace him, so I have to go with the conservative."

"Carter gave amnesty to the draft dodgers, then he gave away the Panama Canal," Bradburn said. "He says he's a born-again Christian and we know that" -- he pauses to snort -- "is a lot of hypocrite doubletalk. And the economy, well, it speaks for itself."

With the word economy, Doskicz saw the opportunity he had been waiting for.

He turned to the rhetorical instrument of dissection that is one of his favorites: Japan, and Japanese import cars.

"Look," demanded Doskicz, "why is the auto industry so messed up? Why do I have a little run-down Datsun sitting out in front of my house? You know why? Because in 1974 and 1975, the auto industry came out and said that they could not make small economical cars with high gas mileage. They didn't see what 20 million other people saw, who went out an bought all those Japanese cars because they were getting 40 miles to the gallon."

The thoughts of John Doskicz, stored up privaately for months, unravel for minutes. Finally, he let it all out with this cutting assessment. "The auto industry didn't budget right, they didn't forecast right, they didn't manage right. So let's lay the blame where the blame belongs, that's all I'm saying."

Dosckicz had made his point. Bradburn retreated a little on the issue of the economy, and departed.Doskicz was left in his shop with the joy of having influenced an opinion, and a new strength of conviction in one of his own. With other visitors on the other days, he will talk of the military, inflation, and national leadership. Little by little, his thoughts will unroll for his friends, and as they do he will see, even as they will, how he must vote.

The raft of political obituaries for the Anderson campaign last week should have helped resolve the 1980 presidential choice for Dianne and Charles Betsey of Silver Spring -- or so it seemed.

As confirmed liberals who abhor Reagan and are deeply disapointed with the Carter record, they have vowed to vote for Anderson unless convinced that a vote for the independent would help throw the election to the Republicans.

Last week's reports on Anderson's waning strength appeared to say exactly that. But the Betseys both decided to discount them -- a decision confirmed during an after-dinner talk, uninterrupted by television or radio bulletins, with the day's newspapers laid aside in the next room.

"It was just too consistent," Charles Betsey, an economist, said of the reports of Anderson's demise. "On the same day, it was in The Post, The Star and on Walter Cronkite: All of a sudden, that's it for John Anderson. I just resented it."

"Did you resent that? It made me angry too," answered Dianne Betsey, obviously glad to hear her husband echo her own view. "I felt like I was being manipulated. Then the same week, I hear on the radio that Anderson has gotten on the ballot in all 50 states. I just don't see how he could be finished. It's like George Orwell and 1984: Doublethink."

Except for the issue of Anderson's strength, there are no unknowns for the Betseys in the 1980 presidential race. Carter has been such a bitter disappointment -- a string of flipflops, ineptitude and unfulfilled promises, they say -- that they don't want to vote for him again "unless we have to."

Earlier this month, they said they would look to the polls to tell them whether they "have to" vote for Carter. Last week, even that outside factor lost influence. Now they plan to reseve judgement until election day, possibly until they go into the voting booth, rather than give up on Anderson. p

"If something upsets me deeply a half an hour before I go in to vote, I'm not going to lie: it could change my vote," Dianne Betsey said.

Charles Betsey said he, too, plans to go down to the wire. And the choice the Betseys make when they get there will likely turn on what they conclude in their living room the night before.

On a comfortable suburban street in Gaithersburg, another kind of conversation is taking place these days between Jerry and Judith Eisenberg, who teeter on the brink of abandoning hope for a reasonable choice, and their old friend Dan Walder, who has chosen and would like them to choose.

The Eisenergs, a young professional couple who have earned a comfortable suburban life, have been close to Dan and his wife Kate for years, and each election has found them in a living room late at night, talking over their choices.

This year, the Eisenbergs are not sure that they have a real choice, or that their decision, and when they make it, will have any meaning for them. "We're very pragmatic," says Jerry. "And when we have a decision, we ask first, what will the consequences be of not making the decision, and what will the consequences of a wrong decision be. In this case there will be no real consequences."

Dan, equally comfortable in life, might agree with that attitude, but feels strongly that voters can -- and must -- make a choice that is "meaningful and positive." So he trys to tell the Eisenbergs on their evenings together how he can choose Reagan, "subject to change" in a way that makes sense.

It's not an easy job. Argument tends to move in cycles, beginning with a news item, moving to Reagan and Carter, and ending with Dan's attempts to build an argument that cannot be drowned in a tide of cynicism. The subject wanders from the military to social security to air pollution to inflation, but Dan has little luck. "The whole thing just makes you cynical," repeats Jerry. "I'm sure Reagan is just saying what you want to hear. Carter is no different from Reagan, and this is no different from any other presidential campaign."

And so, Dan turns to an argument that Ronald Reagan and Jimmy Carter would never think of, tailored to the disenchantment the Eisenbergs share and that he himself feels.

He drops his discussion of the issues to say that even when candidates cannot be clearly distinguished, he can choose inteligently because he believes in change itself, in the new blood that will invariably bring something healthy to government.

On this level, Jerry can reach a conclusion, even if it is the opposite of Dan's. "That's why I might vote for Carter," he says, "because if you don't see the issues as relevant, why make a change? You don't know what you're getting."

Jerry does not decide for Carter on that basis, but the talk, he says, has helped. "We don't get much information from the media," he says, "a gem of information here or there -- so it's got to come through discussions like this."