AUGUSTA — The Passamaquoddy Indian tribe’s proposal to build a racetrack-casino in eastern Maine, which has been turned back by three gubernatorial vetoes in two years, trailed steadily as returns were being counted from Tuesday’s referendum.

Unofficial returns from 75 percent of the state’s precincts showed the racino proposal behind by just shy of 4 percentage points, while a proposal to extend term limits was rejected by a solid 2-1 margin.

The racino question, sent to voters through a citizen initiative led by the tribe, proposed doubling to 3,000 the number of slot machines allowed in the state. Plans for the Down East racino would be subject to local approval.

“We continue to be optimistic,” Passamaquoddy Lt. Gov. Joe Sockabasin said as the Yes on 1 campaign monitored tallies. Opponents said they were not ready to claim victory.

Also on the ballot was a proposal to extend from four to six the limits on consecutive terms for state legislators, effectively allowing them to serve a maximum of 12 instead of eight uninterrupted years in the House or Senate. The question was sent to voters by the Legislature.

The racino proposal generated most of the interest on the statewide ballot, which also included three bond issues. If passed, the racino would have to be least 90 miles from the existing commercial track that operates a Bangor racino, Hollywood Slots.

The Passamaquoddy Tribe has an option on land in Calais, on eastern Maine’s border with Canada, for a harness racing, gambling and destination resort. The ballot proposal would also allow high-stakes beano.

During the campaign, the Passamaquoddy Tribe and other racino supporters said past promises to lift Washington County from its chronic economic morass have failed. They said the racino complex and spinoff businesses would bring economic development at no cost to government.

The issue of fairness was an undercurrent to the campaign. Supporters asked why a Maine Indian tribe should be denied an opportunity to operate slot machines while approval has already been granted to an out-of-state business, Penn National Gaming Inc., to run Hollywood Slots.

The referendum was sent to voters when Gov. John Baldacci earlier this year vetoed an initiated bill to allow the racino. He had vetoed two similar bills since 2005, claiming that gambling is not a sustainable form of economic development for the state.

Other opponents, led by Casinos NO!, warned that a large share of gambling revenues would come from Maine families, whose money would wind up in corporate pockets.

Opponents also voiced concerns that increased gambling would attract criminal elements, and said no provision in the bill gives local voters a say over whether to allow high stakes beano in their community.