AUGUSTA – The campaign leading to next month’s statewide referendum to increase state aid to local schools by more than 25 percent is shaping up as a grass-roots effort with minimal spending on advertising.

When the initiative first went before voters last November, the two sides spent a total of more than $2 million, much of it on expensive television ads. This time, neither campaign has much cash in hand to finance an advertising blitz.

The turnout for the June 8 vote is likely to be a lot lower than it would be for the general election Nov. 2. So it makes more sense for activists to focus on getting their people to the polls next month, instead of spending a lot of money to win over undecided voters who may not bother to cast ballots.

Spearheaded by the Maine Municipal Association, the proposal going before voters a second time would immediately hike the state’s share of local school costs from about 43 percent to 55 percent of the total.

The pending referendum, known as Question 1A, got more votes last November than a competing plan backed by Gov. John Baldacci and the Legislature. But Question 1A’s win was not decisive enough to push it over the top, forcing a stand-alone follow-up vote.

The tax-relief plan is the only statewide question on the primary ballot next month. None of the congressional primaries are contested, reinforcing the likelihood of a low June turnout.

Both sides hoped the Legislature would settle the issue by coming up with an alternative tax reform plan before June. Lawmakers instead went home empty-handed April 30, leaving no time and little money for a full-blown campaign before the referendum.

“We were waiting forever to see if the Legislature could come up with a compromise we could live with,” said Robert Walker, president of the Maine Education Association, which represents teachers and supports the referendum.

Dana Connors, a leader of the opposition to Question 1A last fall, said his group is in the same situation. “There wasn’t a strong attempt to raise money” for the June vote, he said.

State campaign records filed in April showed organized supporters of Question 1A with a mere $5,535 in the bank. A political action committee that opposes Question 1A listed $6,134 in cash on hand.