GIVEN THE PRIMACY of primaries in this heavily one-party city, there usually isn't a whole lot left to decide on the local level in November. Even Mr. Mondale can harbor serious thoughts of his own predicted mini-landslide here. But this year, local politicians and voters have the makings of a fascinating election for one of two at- large D.C. Council seats up for election: a candidate who is not on the ballot might steal the show and save his seat.

Write-in candidacies are, of course, the longest of shots. Yet it seems that Carol Schwartz, winner of the Republican nomination, has her hands full in Round 2: Jerry A. Moore Jr., the incumbent whom she defeated, currently looks to be the most draftable man in town, with heavy, influential support in his corner.

Provisions were written into the D.C charter on Capitol Hill to placate congressional Republicans concerned about the lopsided Democratic registration. Two seats on the 13-member council may not go to the majority party, which is how Republican Jerry Moore and Statehood Party member Hilda Mason have been able to make it to the council over the years. Up to now, their nominations by their parties have been reason enough for most people in all three parties to vote for them in the general election. This time, though, a majority in a GOP minority voted to deny Mr. Moore the GOP nomination. Now, there are Republicans, Democrats and independents who believe that Mr. Moore can attract a majority of the across-the-board majority -- if enough people write in, stamp in, sticker in or otherwise cite him on their ballots. The immediate question -- which the D.C. elections board is supposed to answer today -- is which of these methods will be allowed and how much help the board will offer.

Write-ins are by law allowed, so that much is settled.We see no reason for banning stamps or stickers with the correct, legible spelling of a voter's preference -- but with at least two stipulations. Stickers, says the board, will gum up the ballot counting; while nothing could gum up things more than the board itself used to back in the election- nightmare days, a ban on stickers is reasonable. But rubber stamps are fine, so long as the board isn't in the business of providing them. That wasn't clear initially, though yesterday board officials said they never intended to make up or offer stamps, with the possible exception of help for handicapped. If a campaign wants stamps, that's a job for its workers -- outside the polling places.