Two of the Republicans running for Pennsylvania governor would like to eliminate school property taxes, while a third says it's a bad idea.

The winner of Tuesday's primary will run against Gov. Wolf, a Democrat who has said he is open to ending the reliance on property taxes as a source of revenue and supported the idea in his 2014 campaign. But in office, Wolf has opposed bills to eliminate school property taxes, citing concerns with the details and proposed revenue replacements.

Paul Mango, an Allegheny County health-care consultant, and Scott Wagner, a business owner and state senator from York County, have made property-tax elimination part of their gubernatorial platforms. But the third GOP candidate, Pittsburgh attorney Laura Ellsworth, warns that their support for replacing it with increased sales and income taxes is a risky way to fund education.

All three candidates say various taxes in the state are too high and have offered proposals to reduce them and rein in spending — a topic likely to get more traction in the general election this fall. The property-tax issue is one key point on which the Republicans differ. But if history is an indicator, the tax will still be here after the November election.

Candidates' vows are simply campaign promises at this point, said Gerry Cross, executive director of the Pennsylvania Economy League.

"The executive can promise, but until the legislative and the executive can deliver, it's still a promise," Cross said.

A recent push on the issue in Pennsylvania — including a constitutional amendment approved by voters last year and a tied Senate vote in 2015 on a bill that Mango and Wagner now both support — has drawn attention to the issue of property taxes ahead of this year's race for governor.

"Taxes have always been sort of a central part of campaigns," said G. Terry Madonna, poll director and a professor of public affairs at Franklin and Marshall College. "There has been a much heavier emphasis by two of the three Republican candidates on it."

Polls of voters find that property taxes are "by far … the most unpopular tax," Madonna said. But if voters learned that eliminating such taxes would cause their income and sales taxes to increase substantially, he said, "you might get a different response."

In a debate last week televised on WGAL, an NBC affiliate in Lancaster, Mango said he supports a bill that would replace school property taxes with increases in the state income and sales taxes. The bill, which would still keep some school property taxes in place for districts to pay off their existing debt, failed to pass the Senate in 2015 when Lt. Gov. Mike Stack III broke a tie vote.

"If the local school district [now] wants to increase spending … they have to go the people and ask them in a referendum," Mango said of the bill, known as the Property Tax Independence Act. "Some have said, 'Oh my gosh, this will take power out of the school district and move it to Harrisburg.' It's the opposite — it's going to move power out of the school district and give it back to the people."

Wagner is a co-sponsor of the bill, and has cast himself as the candidate who can end property taxes."My goal as governor would be to eliminate school taxes on real estate," he said in the debate.

Wagner and Mango have criticized each other's campaigns for slight differences or shifts in their stances on real estate taxes or other tax issues.

Ellsworth, meanwhile, disagrees with both of them. She said she would provide relief to seniors by freezing property taxes for residents who have paid them for more than 35 years, but she does not believe the state should end its property tax dependence.

"When you have market-based taxes like income or sales tax, when we have a crash, as we have had in our recent past, when people aren't buying things and they aren't making things, you can't have the entire funding system of our schools crash as the same time," she said. "Property taxes provide stability and predictability for our educational system, and that is important."

Wolf, who has no primary opposition, has voiced concerns with the bill that Wagner and Mango support because it would expand the state sales tax to include food and clothing; the governor's office has also said that education funding remains a priority and that Wolf does not want to hurt school districts.

Because real estate taxes are levied by school districts, counties, and municipalities, Cross said it is interesting that candidates for governor are spending time talking about it. State action to transform the way schools are funded, he said, is a debate with broad implications.

"I don't know if the argument is so much 'eliminate property taxes,'" Cross said. "Maybe the argument is: What's the state's role in paying for public education?"