THERE ARE THREE serious candidates for governor in Virginia, but only two of them will be on stage next month for the campaign's first formal debate. State Sen. H. Russell Potts Jr. (R-Winchester), a maverick who has infuriated the GOP establishment by mounting an independent candidacy, is being barred by the debate's sponsor, the Virginia Bar Association, in league with the Republican nominee, former attorney general Jerry W. Kilgore. It's no great secret that Mr. Kilgore fears Mr. Potts may draw off moderate Republican votes and harm his chances in the general election. But wouldn't it be nice if Mr. Kilgore tried to outshine Mr. Potts in a contest of ideas rather than by trying to make him disappear?

For months Mr. Kilgore has been accused by Lt. Gov. Timothy M. Kaine, the Democratic candidate, of seeking to squiggle out of debates altogether. Mr. Kaine, by far the more polished debater, says he has accepted 11 sponsors' invitations to debate; so far Mr. Kilgore is certain to show up only at the bar association event in mid-July and one other debate in September. Mr. Kilgore may prefer a scripted and stage-managed campaign with few debates, but voters deserve a freewheeling exchange that sheds light on each candidate's grasp of the issues and quality of thinking.

Mr. Potts should take part in that exchange. The scion of a politically active Republican family whose roots in Winchester extend to the Civil War, Russell Potts was elected to the state Senate in 1991. His plain-spoken delivery brings a sensible, lucid approach to the issues. He seems to have collected enough signatures to appear on the ballot in November. Voters are entitled to the benefit of his views. If Mr. Kilgore lacks the confidence to debate Mr. Potts, does he really possess the self-assurance to govern?