Chief Justice John Roberts
CNN  — 

A 5-4 Supreme Court reinstated a Trump-era rule Wednesday that restricts the authority of states to reject federal permits under the Clean Water Act in another ruling putting the court’s emergency docket in the spotlight.

Chief Justice John Roberts joined the court’s liberal justices in dissent, arguing that the court’s majority had “gone astray” by granting an unwarranted request on its emergency docket.

“That renders the Court’s emergency docket not for emergencies at all,” Justice Elena Kagan wrote for the four dissenters. She said that the Republican-led states and others that had petitioned the court for emergency relief had not shown they would suffer the necessary irreparable harm to make their case.

“This Court may stay a decision under review in a court of appeals only in extraordinary circumstances and upon the weightiest considerations,” Kagan wrote. She said the challengers’ request for a stay rested on “simple assertions – on conjectures, unsupported by any present-day evidence.”

The majority’s move, Kagan insisted, signals the court’s view of the merits even though the applicants have failed to make the irreparable harm showing “we have traditionally required.”

The emergency docket, she said, “becomes only another place for merits determination – except without full briefing and argument.”

The five conservative justices did not explain their reasoning for reinstating the Trump-era rule.

The emergency docket – referred to by some justices and outside observers as the “shadow docket” – has increasingly come under criticism by those who say that important issues are being resolved without the benefit of full briefing schedule and oral arguments.

While the court’s liberals, especially Kagan, have often criticized the use of emergency petitions, this is the first time Roberts has explicitly joined in.