The chairman of the District's Board of Elections & Ethics has tendered his resignation, raising the possibility that the Sept. 14 Democratic primary vote won't go through.

To ensure that it does, the mayoral opponents will have to work together to fill at least one of two vacant board spots.

Errol Arthur told The Washington Examiner on Tuesday that he had to step down because his new job as a magistrate judge at D.C.'s Superior Court will present too many opportunities for a conflict of interest. He said he notified the mayor's office last week.

The timing of his leaving the board couldn't be worse.

Arthur's last day will be Aug. 2, just weeks before the primary that will likely determine the District's next mayor. The three-member board has been running with only two members since February 2009, and if a replacement can't be found quickly, there won't be a board in place to verify the primary votes. In other words, it'll be as if the primary never happened, officials said.

The situation has the D.C. Council and the mayor working behind the scenes to agree on nominees. The council isn't supposed to return to session until after the primary, so members will have to convene an emergency meeting to vote on the nominees, officials said. That will require Mayor Adrian Fenty and Council Chairman Vince Gray to put aside their differences in their race to be the city's next mayor, and work together to make the election possible.

The board will have to move quickly to meet again before Aug. 2 and square away the final administrative details, said Board of Elections & Ethics Executive Director Rokey Suleman.

As chairman, Arthur oversaw some of the board's toughest decisions, including its ruling not to allow a referendum on a proposal that would have defined marriage as between a man and a woman.