BARBARA WALTERS, moderator of the debate, apologized. Dorothy Ridings, president of the sponsoring League of Women Voters, says the two presidential campaigns "abused" the process. New York Times reporter Gerald Boyd said, "I just did not feel that kind of procedure was desirable and I did not want to participate in it." What prompted these regrets and complaints was the procedure used by the league to select journalists to question President Reagan and Walter Mondale Sunday.

The procedure worked raggedly. As in the 1976 and 1980 debates sponsored by the league, each campaign was given the chance to veto certain journalists and keep them off the panel. This year, however, the veto was used more often than in the past. In 1976 no panelists were vetoed, and in 1980 one was. This year league officials said, 112 names were submitted to the campaigns before they could come up with four acceptable to both -- a number reduced to three when Mr. Boyd declined to serve. Spokesmen for both campaigns deny they vetoed -- or even saw -- anything like 112 names, and that they rejected primarily journalists they didn't know, whose ability and objectivity they couldn't judge on short notice. Both argue that if they and the league had given the procedure more time and attention, agreement could have been reached more easily.

That assertion will be tested soon. Two reporters have been chosen for the vice presidential panel on Thursday, leaving two more to be agreed upon; none of the panel members for the Oct. 21 presidential debate has yet been selected. We continue to believe it would be better not to have panels of journalists at all, to let the candidates speak directly to the voters and each other; this is what the Mondale forces wanted, but the Reagan campaign insisted on having questions asked by a panel.

The Washington Post has decided to bar its reporters covering the campaigns from appearing in the debates. But others feel differently, and, given the controversy, it is only fair to record that we think the panelists in Louisville performed their duties professionally and fairly. The dispute over "blackballing" journalists seems to be more a matter of misunderstanding than of any blameworthy conduct by anyone, but it will have served a useful purpose if it turns out to signal the end of involvement by journalists in the debate process.