On Thursday, the Supreme Court dealt a major setback to President Joe Biden’s ambitious climate change goals, ruling that the Environmental Protection Agency lacks broad authority to reduce greenhouse-gas emissions from power plants.

The 6-3 decision puts Biden’s hopes of addressing global warming through executive branch action in jeopardy, just six months after a Senate stalemate stymied congressional Democrats’ efforts to pass their largest-ever climate bill.

Furthermore, the ruling may raise concerns about other types of regulation in which agencies seek to use older statutes to address emerging and ongoing social problems, such as in health care, telecommunications, finance, and other major sectors. Biden called the ruling “another devastating decision that aims to take our country backwards” in a statement.

The conservative majority’s decision on Thursday stated that the EPA cannot take the broad approach that the Obama administration had taken in regulating greenhouse gases from the nation’s power plants. It also placed the onus on Congress, which has been unable to pass major climate legislation since Democrats’ cap-and-trade bill died 12 years ago, to give the EPA more authority to combat climate change if lawmakers want the agency to act aggressively.

Democrats’ hopes of passing major climate legislation have been put on hold since the failure of Biden’s Build Back Better plan last year, which included more than $500 billion for climate-related efforts. And the door for congressional action is narrowing as Republicans are expected to retake at least one chamber in this fall’s midterm elections.

Following Thursday’s decision, Biden’s options for addressing climate change through existing laws are also dwindling.

The Supreme Court ruled that the Obama administration’s 2015 climate rule, which sought to shift states away from coal and toward natural gas and renewable sources, was a “unprecedented” and illegal expansion of the EPA’s power.

“Today, the Court strips the Environmental Protection Agency (EPA) of the power Congress gave it to respond to ‘the most pressing environmental challenge of our time,'” Justice Elena Kagan wrote in her dissent, citing an earlier climate decision.

In his statement, Biden stated that the administration would review the decision and consider how to continue regulating greenhouse gases and other forms of air pollution. “While this decision risks jeopardizing our nation’s ability to keep our air clean and combat climate change,” the president said, “I will not back down from using my lawful authorities to protect public health and address the climate crisis.”

The Supreme Court ruled 15 years ago that the EPA has regulatory authority over carbon dioxide and other pollutants that contribute to climate change. However, the new, more conservative Supreme Court ruled on Thursday that its authority to act aggressively to reduce carbon pollution is relatively limited.

Scientists have warned that nations are running out of time to avoid the devastation caused by global warming, and that governments must take more aggressive measures if they are to keep their promises under the 2015 Paris climate agreement. The United States is the world’s second largest source of greenhouse gas pollution, trailing only China, and electricity generation is the country’s second largest source of emissions, trailing only transportation.

Since the Obama administration enacted its major power plant rule, the Clean Power Plan, in 2015, the scope of the EPA’s authority has remained an unanswered legal question. That rule was based on a complex scheme aimed at convincing states and utilities to abandon coal as an energy source in favor of natural gas or renewable energy.

The Obama EPA took a broad view of the industry, arguing that the rule reflected utilities’ ability to shift fluidly between generation sources — a distinguishing feature when compared to other industries such as oil refining or steel mills. It established targets for states to reduce carbon pollution while allowing for flexibility in meeting those targets in order to promote the most cost-effective solutions.