A state battle over climate-change legislation in 2008 is leaving former House Majority Leader Adam Hasner to explain to the GOP base why he voted for a measure that appeared to bring the state closer to a cap-and-trade system -- a policy that is anathema to most conservatives.

Hasner responds that the bill was actually an attempt to fight a climate-change proposal being pushed by one of his opponents.

The topic most recently cropped up in Hasner’s interview with Ray Junior, a conservative talk-radio host who had already tangled with another Florida Senate candidate. Junior emerged from relative obscurity this year when he hung up on Senate President Mike Haridopolos, R-Merritt Island. Haridopolos refused to answer a question on whether he would support a plan by U.S. Rep. Paul Ryan, R-Wis., to essentially convert Medicare to a voucher system.

Haridopolos eventually said he would like to see changes to Ryan’s plan and would not vote for it in its current form.

Hasner, Haridopolos, former U.S. Sen. George LeMieux and tea party-backed Mike McCalister are the major contenders for the nomination to face incumbent Sen. Bill Nelson in the 2012 elections.

On the show this week, Junior pressed Hasner on his support for House Bill 7135 in 2008, a measure that appears on its face to set the stage for instituting a cap-and-trade system -- something Hasner said he didn’t support.

“Never did you vote for, or co-sponsor, or co-author any bills that were for cap-and-trade in Florida, am I correct?” Junior asked Hasner at one point.

“You are absolutely correct,” Hasner said.

Pushed harder by Junior, Hasner portrayed his effort as an attempt to derail then-Gov. Charlie Crist’s plans to implement cap-and-trade and other measures to combat human contributions to global warming.

“We passed legislation to block it,” Hasner said. “And the fact is, that we don't have cap-and-trade in Florida specifically because of that legislation.”

The bill does seem to approvingly mention cap-and-trade.

“The Legislature finds it is in the best interest of the state to document, to the greatest extent practicable, greenhouse gas emissions and to pursue a market-based emissions abatement program, such as cap-and-trade, to address greenhouse gas emissions reductions,” it says.

The measure also gives the Department of Environmental Protection the authority to adopt rules for that system, though it requires them to be ratified by the Legislature before taking effect.

But Hasner’s camp says the legislation wasn’t what it seems. Instead, adviser Rick Wilson said, Hasner’s legislation was a “poison pill” that led to the dismantling of Gov. Charlie Crist’s plans for a cap-and-trade system -- plans that were spearheaded by LeMieux, Crist’s first chief of staff, Wilson pointedly noted.

The plan essentially cut off Crist’s efforts to impose a variety of carbon-reduction measures through executive order and require them to come back to the Legislature, where they would face a more critical reception.

“The Legislature was never going to approve a cap-and-trade bill. ... This was a bill designed to short-circuit a cap-and-trade system,” Wilson said.

Environmentalists, he said, opposed the bill as a setback to their efforts.

Susan Glickman, director of the Florida Business Network for a Clean Energy Economy, remembers things slightly differently.

“Clean energy advocates looked at House Bill 7135 as a real win and an opportunity to move forward,” Glickman said.

In some ways, though, Glickman bolstered parts of Hasner’s comments.

“It did not set up a cap-and-trade program,” she said.

Instead, the thrust of efforts in the state at the time were to prepare the state for the possibility of a national cap-and-trade program, an idea that was gaining momentum at the time, or for any regional efforts to address climate change. A Florida-only system wouldn’t have made sense, Glickman said.