Environmental groups and local governments celebrated in December when the Pennsylvania Supreme Court blocked a law championed by the Corbett administration that had stripped local governments of their ability to regulate natural gas-drilling activities.

But what raised the eyebrows of many who read the 162-page ruling was the reasoning behind it.

The court said that the Environmental Rights Amendment to the state constitution was serious when it stated that Pennsylvania citizens today and in the future have a “right to clean air, pure water, and to the preservation of the natural, scenic, historic and esthetic values of the environment.”

Pennsylvania is one of the few states that promise a clean environment in its constitution, but the Environmental Rights Amendment had largely been ignored in court decisions — and certainly not taken literally.

So it came as a surprise when the court rejected changes made to the Pennsylvania Oil and Gas Act by the General Assembly in 2012, saying they would unquestionably have a “lasting, and undeniably detrimental impact” on the state’s environment and therefore were at odds with the amendment.

The legislation, known as Act 13, would have prevented local governments from using their zoning authority to regulate activities related to the state’s natural gas boom in order to create an easier regulatory climate for drillers seeking to extract natural gas from the state’s rich Marcellus Shale formation. The law further required local governments to allow drilling and related activities in all land uses — including residential, commercial and agriculture — despite any concerns local governments might have about environmental impacts.

“By any responsible account, the exploitation of the Marcellus Shale Formation will produce a detrimental effect on the environment, on the people, their children, and future generations, and potentially on the public purse, perhaps rivaling the environmental effects of coal extraction,” the court said.

Various observers have described the ruling as a potential “game charger” and able to turn state environmental regulation “upside down.” While the commonwealth had argued that the Environmental Rights Amendment delegated natural resource protection issues to state government and the General Assembly, the court said local government also had a stake, and that citizens had a “reserved right” to ensure that resources were protected.

The exact impact on future decisions is unclear. The court has seven members, but because of a vacancy, only six justices participated in the ruling. Four justices agreed to overturn much of the law, but only three of them signed onto the Environmental Rights Amendment portion of the ruling — one vote short of an outright majority. The fourth justice agreed to overturn the law for due process reasons.

“For it to be given true, full precedential effect, there would need to be another piece of legislation, or another portion of this case, brought before the court that would be signed on by four Supreme Court justices,” said Mike Helbing, a staff attorney with the environmental group Citizens for Pennsylvania’s Future.

“That is something that will be up in the air for a little while, and something that will probably take several years if not longer to settle out,” he said.

The opinion, written by Chief Justice Ronald Castille, noted that the Environmental Rights Amendment was one of five amendments voters considered in 1971. It was approved by a 4-to-1 margin, while two other amendments were approved by smaller margins, and two were rejected.

Castille, a Republican, put the amendment in the context of the state’s long history of resource exploitation, including the clear-cutting of its forests, the pollution legacy left from the coal industry and numerous environmental disasters.

Given that legacy of “virtually unrestrained exploitation,” Castille said the drafters of the amendment and the voters who approved it were keenly aware that it set forth both “the people’s rights and the government’s duties to the people” to protect the environment and that those responsibilities were delegated to “all branches and levels of government.”

The state had argued that the amendment left it to the General Assembly to determine the best policy for natural resources, with no inherent right given to citizens or local governments.

But the court said the state’s position sought to minimize the importance of the suit by depicting it as a policy dispute by a disappointed minority. The court said the state’s position “requires a blindness to the reality here and to Pennsylvania history, including constitutional history; and the position ignores the reality that Act 13 has the potential to affect the reserved rights of every citizen of this Commonwealth now, and in the future.”

The ruling did not strike down the law in its entirety. It left in place an impact fee the industry is charged to extract gas, and a requirement that it disclose chemicals used when “fracking” to extract gas.

The Corbett administration blasted the ruling, saying the court “made its own sweeping factual findings” and asked that the court reconsider its ruling.

Because the ruling remanded some of the issues to the Commonwealth Court, Helbing said it is possible the issue could return to the Supreme Court soon, giving the amendment interpretation another chance to gain votes. He said environmental groups would likely look for other suitable cases that would allow the court to expand on the ruling.

In the meantime, he said, “the fact that it is a plurality opinion doesn’t mean that it is worthless. It is something that lower courts can — and I would assume will — consider when reviewing future cases on the Environmental Rights Amendment. So I think that is something we will see regardless of anything else that happens with the Supreme Court.”

PA Environmental Rights Amendment

“The people have a right to clean air, pure water, and to the preservation of the natural, scenic, historic and esthetic values of the environment. Pennsylvania’s public natural resources are the common property of all the people, including generations yet to come. As trustee of these resources, the Commonwealth shall conserve and maintain them for the benefit of all the people.”

Approved by Pennsylvania voters 1,021,342 to 259,979 on May 18, 1971.