Massachusetts' voters will be asked Nov. 4 whether to eliminate the state income tax. Until then, opponents and supporters will be campaigning hard to convince voters.

With ballot signatures certified last week for the proposal initiated by the libertarian group Committee for Smaller Government, the push to repeal the state income tax is officially on. And it creates a lot of opposition.

If the proposal passes, the state would lose $12 billion a year, a 40-percent cut in annual revenue that opponents say would gut local aid to communities across Massachusetts.

"We already have a $1 billion shortfall in the budget with the state income tax," said Michael Widmer, president of the Massachusetts Taxpayers Foundation, which opposes the repeal. "Without the tax, it would be a $13 billion shortfall."

If local legislators, cities and towns and major interest groups are opposed to it, they all concede there is a good chance the proposal will be approved by voters fed up with rising living costs and gasoline prices. "This is a very difficult time for many people," Widmer said. "And that's the problem. I take it very seriously because if it passes, it will be a huge problem."

A similar proposal in 2002 got 45 percent of the vote.

Widmer said that even if there was also a recession that year, there was not the surge in prices that people face today. And that could make a difference.

Geoffrey Beckwith, president of the Massachusetts Municipal Association, said repeal of the income tax would have an "extraordinary impact," especially on cities and towns already struggling with their budgets.

"It would make a very bad situation an unimaginable one," he said.

But Carla Howell, president of the Committee for Smaller Government who filed the petition for the second time, said the state will survive without the income tax.

"When we end the income tax, politicians on Beacon Hill will still be collecting $17 billion in other taxes and revenues," she said.

Her group collected more than 20,000 signatures to support the proposal, far more than the 11,099 needed to place it on the state's general election ballot in November.

Howell said she is optimistic about the vote's outcome.

"We have a good chance to get it passed," she said. "We've been hearing from people collecting signatures that a lot of people are enthusiastic about that." Howell said hundreds of volunteers will focus on a grass-roots effort.

"We encourage volunteers to go to our Web site, send links to their co-workers and friends to learn about the state income tax and our campaign, write letters to newspapers editors, call and talk on the radio, put up yard signs," she said. "We don't have a specific plan yet, but we'll be calling out to volunteers to end the state income tax."

It's shaping up to be an epic battle.

Already, opposition is mobilizing in the state, led by the Coalition for Our Communities, a group comprised of the Massachusetts AFL-CIO, several communities, non-profits, businesses and individuals.

The AFL-CIO is calling on all unions to join the coalition and urges on its Web site to oppose "the decimation of local aid to cities and towns, and the inevitable property tax increases to provide the necessary funding for our schools, police and fire protection, emergency medical services and transportation infrastructure."

State officials and legislators also vowed to fight against the repeal, along with interest groups such as the Massachusetts Teachers Association and Blue Cross/Blue Shield.

Beckwith said that although the municipal association won't directly campaign against the proposal because it is not a political organization, it will comment on implications of the repeal.

"We'll do educational work on it," he said. "We will be informing anyone interested in listening about the impact of such a measure."

Widmer said his organization will start work on an analysis on the impact of the measure as soon as the state budget is complete next month.