The Biden administration seems to be heading for a sobering defeat in the Supreme Court in a battle over environmental regulation. 

The court's conservatives appeared inclined Wednesday to block a "good neighbor" rule meant to lower pollution that drifts across state lines.

Three Republican states, Ohio, Indiana, and West Virginia, and industry groups have asked the Supreme Court to block the rule while litigation proceeds in lower courts.

Biden's "good neighbor" rule

The Clean Air Act requires "upwind" states to limit interstate air pollution, but states are allowed to draw up their own plans for meeting this obligation pending EPA review.

In 2022, the Biden administration rejected 23 individual states' plans in one fell swoop and introduced its own nationwide plan.

In their brief to the Supreme Court, Ohio, West Virginia, and Indiana argued the Clean Air Act requires "cooperative federalism" rather than the top-down approach the Biden administration has taken.

"The EPA has power to impose a federal plan only if a State fails to submit a statutorily compliant plan," the states wrote.

The challengers say Biden's plan imposes "irreparable harm" every day the rule remains in effect, through crushing compliance costs and increased risks to the electrical grid.

Seven different appeals courts have temporarily blocked the EPA, leaving the rule in effect in just 11 of the original 23 "upwind" states covered.

Supreme Court blocks Biden...again

The Supreme Court appeared skeptical this week of letting the EPA enforce the rule since it has already been blocked in half the states covered by it.

“EPA came back and said, 'Even if we have fewer states, we're going to plow ahead anyway,'' Brett Kavanaugh said. "Let's just kind of pretend nothing happened and just go ahead with the 11 states."

The high court has frustrated Biden's ambitious climate agenda in the past. In the 2022 case West Virginia v. EPA, the court struck down Biden's sweeping environmental regulations under the "major questions" doctrine.

Biden hasn't been afraid to call the court's legitimacy into question, blasting its rulings on abortion, climate, and student loans as "extreme."

This week, Biden boasted about finding a workaround to the court's decision striking down his student loan forgiveness plan.

"My Republican friends in Congress, elected officials and special interest stepped in and sued us and the Supreme Court blocked it, blocked it," he said. "But that didn't stop me."