Back in the days when Abraham Lincoln was running for the Congress, ''stumping'' meant a candidate jumping up on any convenient tree stump at the village crossroads and talking to anyone who would listen.
It was an impromptu affair. The audience was made up of ordinary citizens who happened to be there on ordinary daily business. The process gave the voter a chance to see the candidate under ordinary circumstances. They could get to know each other.
Things like that don't happen in American politics anymore. When the candidate goes ''stumping'' now, the process is manipulated. The audience is picked for him by advance agents. He seldom sees or is seen by a cross section of voters. Heckling is unusual and often contrived.
Mostly, today's candidate sees and is seen by only his own faithful supporters, who are organized as a rally. He may sense the existence of doubters in the distance. He seldom gets a chance to exchange ideas and test his own against a critical audience.
The three debates, now concluded, between the top candidates in the 1984 American presidential election have provided a valuable substitute for the long-lost informality of the old stump speeches.
The most interesting camera shots were those of one of the candidates listening while the opponent was speaking. The listener was getting a dose of an opposition point of view. Even more, the voters in the vast television audience had the only chance of the whole campaign to see the two side by side, and listen to their views in alternation, and measure one person and that person's ideas against the other.
Nothing in the three debates is likely to change many votes among the committed partisans of the rival candidates. But it will give to those uncommitted a better sense of what the campaign is all about. There will be more ''informed'' voting among the uncommitted than could otherwise be the case.
Nothing in the three debates has changed the essential feature of this campaign. The issue is not how many voters are for Walter Mondale. When an incumbent president is running for reelection, the personality and policies of the challenger are of minor importance and affect few votes. The question is how many voters are for or against the man in office, who happens to be Ronald Reagan.
The task for Mr. Mondale has been to be a plausible alternative in the eyes of those who want to vote against the incumbent. Mr. Mondale has improved his position in this respect. Until the debates, his political personality was too vague and ill defined to suit many an undecided voter who was inclined to be against Mr. Reagan, but not strongly enough to vote for the pre-debate Mondale.
Mr. Mondale emerges from the debates as a plausible alternative. The polls after the first debate showed that he succeeded in improving his identity in the public mind. He can present his views with clarity and vigor. He has become a positive political personality and thus able to receive more votes.
But most of the people who are going to vote for Mr. Mondale 12 days from now are not going to be voting specifically for him. They will be voting for an alternative to Mr. Reagan because they start out by being inclined against Mr. Reagan.
The real issue, as from the beginning of the campaign, has been whether a majority of the voters want to continue Mr. Reagan's four-year counterrevolution as much as it can be continued by giving him a second four-year term. Thus the election is not for Mr. Mondale to win or lose, it is for Mr. Reagan to win or lose.
Within this context, Mr. Mondale did not win the debates but did win out of them more plausibility as an alternative choice. Mr. Reagan neither won nor lost the debates but did win out of them a continuation of his position as front-runner and the favorite candidate of an ardently loyal section of the electorate.
Mr. Reagan could still, in theory, lose the election, but time is short for doing the unlikely.