An appeals court yesterday ordered the D.C. election board to clarify its decision to invalidate thousands of signatures gathered in support of a plan to legalize slot machine gambling in the nation's capital.

In a five-page order, a panel of the D.C. Court of Appeals suggested that the Board of Elections and Ethics might have overstepped its authority when it threw out the signatures in part because petition circulators made "false statements" to potential signers.

Slots supporters have argued that the board violated their First Amendment right to free speech, and the court indicated that it is inclined to agree. But the election board has countered that the petition drive was marred by so many forgeries and other violations of D.C. election laws that its decision, which had the effect of denying the gambling initiative a spot on the Nov. 2 ballot, can be justified on other grounds.

In yesterday's order, the court instructed board members to make that case more clearly and to do so as fast as possible.

"Although time has become of the essence in this case," the court wrote, "the interest of justice will be furthered by the intermediate step we order."

Time is rapidly running out on the slots initiative, which seeks voter approval for a plan to build a gambling hall with 3,500 slot machines on a 14-acre site at New York Avenue and Bladensburg Road in Northeast Washington. Attorney George Jones, who represents slots supporters, said "there's still some possibility" that the initiative could make this fall's ballot.

"I am cautiously optimistic," Jones said. "I think the ball's in the board's court now. They've got to look at this order and decide what they're going to do."

The board, which was preparing for today's primary election, declined to comment on the court order.

With the election today, "we're all focused on that," board spokesman Bill O'Field said. "Nobody's talking."

Parties to the slots battle said the election board is likely to convene in the next few days to rewrite its decision in the case. Slots opponents said they expect the board to have little trouble convincing the court that a hurried, five-day petition drive in July failed to produce a sufficient number of legitimate signatures in support of the gambling initiative.

"The evidence of fraud was so pervasive, there just isn't any question in my mind that it can't stand," said Ron Drake, a lawyer who filed one of two challenges. "They have no right to put it on the ballot because the fraud is so significant."

Yesterday's order does little to resolve the complicated battle over the initiative; it merely gives the election board a second chance to explaining its decision. The likely path of its argument was laid out in a brief submitted to the appeals court Friday, two days after the court heard oral arguments in the case.

In that brief, the election board's general counsel, Kenneth J. McGhie, offered a numerical breakdown of petition sheets rejected by the board in an effort to prove that slots supporters failed to submit valid signatures of 17,599 registered D.C. voters, as required by law.

Slots supporters initially submitted more than 56,000 signatures. But the vast majority were excluded because the names did not appear on voter registration lists or because the signatures were collected by circulators who admitted in public hearings that they had not witnessed all the signatures or invoked their Fifth Amendment rights. That brought the number down to 19,506, according to the brief.

The board then rejected an additional 418 signatures collected by four circulators who failed to respond to election board subpoenas, bringing the number down to 19,088.

Two dozen additional circulators could not be found by the board, often because they did not live at the addresses listed on the petition forms. Excluding their signatures put the total at 16,553 -- below the threshold required to qualify for the ballot.

The board threw out nearly 2,000 additional signatures collected by circulators affiliated with a consultant to the petition drive, Stars and Stripes USA, after concluding that the Stars and Stripes effort had been "polluted" by forgery and false statements. That brought the number to 14,687.

But those signatures are not critical to the case, Drake said, if the appeals court accepts the argument that the board may invalidate signatures when circulators can't be found to vouch for their work.