Two years after Ohioans rejected legalized casinos in a statewide referendum, it appears they'll have another gambling expansion proposal to vote on Nov. 4.

A group aiming to build a single $600 million casino in southwestern Ohio, between Columbus and Cincinnati, announced last week that it had obtained about twice the 402,000 signatures needed on a petition to get the gambling measure on a statewide ballot. If the secretary of state certifies the petition, it would mark the fourth time a gambling expansion would be put before voters since 1990.

All those prior attempts have failed, and Ohio is nearly surrounded now by Indiana, Michigan, West Virginia and Pennsylvania as states with casinos of some form. The new proposal, because of its single site nearly four hours from Pittsburgh, would have far less potential impact on Pennsylvania slot parlors than the 2006 proposal that would have permitted slots in Ohio at seven racetracks and two additional Cleveland locations.

The casino effort is led by a new group called MyOhioNow, spearheaded by two Cleveland-area residents with no casino experience. They have partnered with Lakes Entertainment Inc., a Minneapolis-based firm that has primarily developed tribal casinos.

The Minnesota firm is putting up most of the money to seek a full-fledged casino resort, including table games and slots, on property in Wilmington, Ohio. The location near Interstate 71 has been used as a farm, said Rick Lertzman, one of the two Ohio principals.

He said Ohio's economic struggles could give the referendum a better chance of passage this year, along with a heavy voter turnout possible among Democrats and younger voters -- whom Mr. Lertzman suggested would be more likely to back casinos than the state's tradition-minded Republicans. This year's proposal is more straightforward, he said, with its single site, holding out the promise of 5,000 new jobs, and with 30 percent of gambling revenue to be disbursed to the 88 counties across the state for local spending.

"The past [ballot] issues were all over the state, and voters seemed not to want that," Mr. Lertzman said. "They looked at it with a wary eye, wanting to see what [gambling's] going to do, and we decided to start slower."

The Ohio Roundtable, a conservative advocacy group, led the opposition when voters rejected the slots by a 57-43 margin two years ago and is poised to do so again. Vice President Rob Walgate said past outcomes don't guarantee anything, because gambling advocates generally have far more money available to advertise and otherwise influence voters.

"The one great thing is the fact that we have the utmost faith in Ohio voters to see this proposal as what it is, a sham," Mr. Walgate said. "A Minnesota company is trying to turn the Ohio constitution into their own personal business monopoly."

He said his group would suggest to voters that if this casino is approved, the door would be open for many others to try to open. The roundtable is also skeptical of the backers' promises that $240 million annually would be generated for county budgets.

"Gambling revenue is on the decline everywhere across the country," Mr. Walgate said. "People will see through the false promises. ... There's a lot of pro-gambling people who will vote against this because it's so bad for Ohio."

If the measure were to succeed, Mr. Lertzman said, its biggest impact would be on three casinos operating less than an hour away in Indiana.