The group behind the successful lawsuit against the way Ohio pays for public education has lost some key allies as it tries to ask voters to force what couldn't be done through court victories.

The Ohio Coalition for Equity and Adequacy of School Funding and a former state representative last week began gathering signatures to put a constitutional amendment on the November ballot that would replace about $2.5 billion in local property taxes now collected by districts with general state taxpayer money.

Major education groups that supported the school funding lawsuit - including teachers unions and associations for school boards, administrators and parent-teacher associations - don't want the amendment.

''I certainly think education needs more money, but to just dump something like that on the state doesn't seem like a policy the people of Ohio would accept,'' said John Brandt, executive director of the Ohio School Boards Association.

William Phillis, director of the coalition of about 500 school districts that sued the state, doesn't feel alone.

''You'll find that the opposition isn't more than skin deep with regard to some of the organizations,'' he said. ''Are you willing to step out and take a risk on behalf of the students of this state or are you going to remain in your comfort zone and give excuses for not providing leadership?''

Phillis' confrontational style has alienated some lawmakers who control how much money schools get, said Tom Sutton, a political science professor at Baldwin-Wallace College who has studied the school funding fight. Even during the Supreme Court case, big education groups that agreed in principle distanced themselves from him.

''Generally their approaches tend to be more: let's work within the system and try to get incremental change,'' he said. ''They're going to stay on the sidelines, and actually may come out in opposition.''

The Supreme Court ruled three times from 1997 to 2002 that the school funding system is unconstitutional before ending its involvement and blocking any more state court action. Lawmakers have not significantly changed how education is paid for.

Because of that history, the education groups say they don't trust the Legislature to obey the amendment, which would require lawmakers to obey a committee that would study school needs and order lawmakers to pay for it. It also would cap local property taxes and require the state to make up the difference.

Lawmakers might argue that the constitution elsewhere says lawmakers don't have to follow orders from another government body, Sutton said.

The southeast Ohio school district that inspired the Supreme Court case has not yet decided whether to support the amendment, but its treasurer has her own worries.

''What says if we change the constitution, that they'll follow it?'' said Elizabeth Arnold, of Northern Local School District in Thornville in Perry County. ''We need to safeguard every asset we have.''

The proposal also would face a ballot crowded with other initiatives, possibly including a constitutional amendment to limit state spending to the rates of inflation and population growth - contradicting the one ordering a big increase in education funding.

About five dozen school districts favor the amendment, and support is growing, Phillis said.

''We understood going in this was going to be a grass roots effort,'' said Bryan Flannery, a former state representative leading the petition campaign, which must gather nearly 323,000 signatures by August. He said about 11,000 petitions have been distributed in a few days.

Groups opposing the amendment say they also worry there's not enough time to raise money to run an election campaign.

The amendment would likely be popular if it gets on the ballot, said John Matsusaka, president of the Initiative and Referendum Institute at the University of Southern California.

''It's go the two things the voters love, which is education and tax limits,'' he said. Even though state money comes from taxes, too, voters typically assume that state money can come from closing tax loopholes or cutting programs they don't like, he said.

The lack of support might hurt if the education groups, especially teachers unions, actively campaign against the measure, Matsusaka said. ''If the teachers say this is bad for education that's going to be a problem.''

Carrie Spencer is a correspondent for the Ohio Associated Press.