At a hearing Thursday, the proposal drew support from many environmental groups, who called the plan a sustainable source of funding compared with the state's usual practice of paying for land through repeated bond referendums.
"Does it make sense for New Jersey, the most densely populated state in the nation . . . to dedicate less than a percent of the state budget" to preserving critical lands and water supplies, asked Tom Gilbert, regional conservation services director for the Trust for Public Land and chairman of the NJ Keep It Green Coalition, which says it represents 180 organizations across the state.
"We would argue it does, without question," Gilbert told the Senate Environmental Committee.
Others countered that the answer wasn't so simple.
"It's not easy or comfortable . . . for an environmental group to express reservations about open-space funding," said Dave Pringle, campaign director for the New Jersey Environmental Federation.
"We clearly desperately need to be replenishing" the fund for open space, Pringle said. "But we also desperately need to be fiscally responsible."
He and other environmentalists opposed to the proposal voiced a larger concern: that the state would pare other programs, some of them environmental, to compensate for the sales tax diverted to open-space funding.
"It's going to mean cuts in other programs or taxes somewhere else," said Jeff Tittel, director of the New Jersey Sierra Club.
"This will allow the governor to cut more," Tittel said, citing Gov. Christie's diversions of money from a clean-energy program.
"The open-space groups only care about open space," Tittel said. "They don't care about other issues."
Gilbert said groups within the Keep It Green Coalition have their own environmental agendas but "a shared commitment" to continuing open-space preservation.
He said "no particular connection" exists between environmental programs and sales-tax revenue - which, he noted, has been used to pay debt service on open-space purchases.
"Some of those groups are rightly concerned about cuts to other environmental programs, but frankly, it's unrelated," Gilbert said.
Opponents of the sales-tax proposal called instead for a water tax, which would create a source of revenue.
A bill proposing a water tax was introduced this year by Sen. Bob Smith (D., Middlesex). The plan died in the environmental committee, which Smith chairs.
"It had no legs," said Sen. Christopher "Kip" Bateman (R., Somerset). "It wasn't going to get out of committee, and it wasn't going to pass the Senate."
That led to the sales-tax proposal. While in past years bond referendums backed by voters have paid for preservation efforts, "there's a lot of concern about increasing the debt," Bateman said. "We thought, this was already a revenue."
Bateman said he was surprised by the arguments from detractors.
"If we have $200 million every year, that's significant," Bateman said.
"Usually the enviromentals get together and stand strong together," he said. "This opportunity may not come around again."
Opposition aside, the measure might not even make it onto the ballot this fall. While the Senate in June voted, 36-2, to dedicate a percentage of sales-tax revenue to open space, lawmakers amended the proposal to cap open-space funding at $200 million a year, or $6 billion over 30 years.
That change required a second public hearing, which was held Thursday.
For the measure to appear on the ballot, the Assembly and Senate both must convene by early August and approve it by a three-fifths majority - a tall order in the summer.
"It's going to take leadership to crack whips," Smith said.
Representatives for Assembly Speaker Sheila Oliver (D., Essex) and Senate President Stephen Sweeney (D., Gloucester) did not respond to requests for comment.
Even if the measure does get onto the ballot and wins voter approval, it would not go into effect until fiscal 2015.
Meanwhile, money from the last land-preservation bonds - $400 million approved by voters in 2009 - has all been spent.
The state might be able to spend some money on open space in the coming year, Gilbert said.
While the sales-tax proposal would not take effect immediately, its passage would assure municipalities and counties they would receive the financial support they needed to buy open space, Gilbert said.
"As long as there's this huge question mark, it's going to have a chilling effect on preservation efforts around the state," he said.
Contact Maddie Hanna at 856-779-3232, email@example.com, or on Twitter @maddiehanna