A special election to determine – once again – the size of the Amherst Town Board is just one week away, but town Democrats are trying to stop the effort before it gets to the ballot box.

Democratic Town Chairman Jerome D. Schad has filed a legal challenge to the special election, where voters would decide whether to keep the six-member board instead of allowing a downsizing to five that would otherwise take place at year’s end.

Schad argues that the Town Board members who initiated the vote – the Republican majority that would lose a board seat – has no legal right to make a second change to the size of town government after voters overwhelmingly approved the downsizing in 2010.

The basis for Schad’s argument rests on the state’s Municipal Home Rule Law, which states that “no local government may restructure its local legislative body ... more than once in each decade.”

Schad takes that to mean that the 2010 vote to downsize the Town Board to five members – a move that was championed then by the Republicans – is indeed that once-in-a-decade change.

“I don’t know a single person from the 2010 vote who said, ‘I don’t want my vote to count,’” he said. “They can’t do what they’re doing. It’s just not allowed.”

Town leaders don’t agree.

“It does not apply to our situation,” said Deputy Town Attorney Patrick M. Kelly, adding that most of the statute deals with issues not applicable to the Town Board.

But Schad has asked State Supreme Court Justice Tracey A. Bannister to determine Wednesday whether the law applies to Amherst and whether the June 11 special election will go forward.

If voters approve a six-member board, no seats will be lost, but if the measure is defeated, one board member will lose his or her seat at year’s end.

Town leaders in 2010 agreed to gradually downsize the board so as not to leave someone without a seat, and Barry A. Weinstein’s seat on what had been a seven-member board was eliminated when he became supervisor.

Weinstein said he is not familiar with the details of the court challenge, but he painted a six-member board as the best option for town voters.

“It’s changed the way government functions in Amherst in the last 3½ years,” Weinstein said. “Special interests used to be able to line up four votes and influence town policy.

But that has stopped since the board was trimmed from seven members to six, he said.

“It’s a lot harder to get four votes out of six than to get four votes out of seven,” he said.

Democrats and civic activist Kevin Gaughan, meanwhile, have said the move is a blatant attempt to save a Republican seat now that the balance of power has shifted in their favor.

They also say that a six-member board – where policy can be snagged on tie votes – is not good government.

“Government should be more stable than just changing because of an election year,” Schad said. “I can’t see any justification in this.”