Environmental groups and aligned states urged a federal appeals court on Tuesday to issue its long-awaited decision on the Clean Power Plan and reject the Trump administration's arguments for holding its ruling in permanent suspension after proposing to repeal the centerpiece of the Obama administration's climate agenda last week.

"This court should deny respondent Environmental Protection Agency's latest request for indefinite abeyance," the coalition of environmental groups argued in a court brief filed Tuesday with the D.C. Circuit Court of Appeals. "Because EPA has not established the necessary grounds for the requested abeyance and because the case involves a time-sensitive statutory obligation to protect the public health and welfare from grave threats, the court should decide this fully briefed and argued case on the merits."

The states that support the climate plan, led by Democratic attorney generals from New York and California, filed a separate brief arguing the same point. "The court should deny EPA's request for further abeyance and decide the case." More than a dozen states support the plan.

The briefs were filed in response to an EPA court update issued last week on the process to repeal the Obama administration's climate plan.

"There is no reason for the court to hold off in issuing its opinion because the same issues underlying the repeal proposal have been fully briefed and argued before the court for over a year," the Clean Air Task Force said in a statement after its lawyers filed their brief on behalf of the coalition, which includes the Sierra Club and Natural Resources Defense Council.

The court heard oral arguments in September 2016 during an unprecedented all-day court session that included nearly all of the court's judges. Scott Pruitt, the current EPA administrator, had fought against the Clean Power Plan when he was attorney general for Oklahoma, with more than two dozen states.

The environmental groups argue that Pruitt is trying to use the legal arguments he made in court to justify why the climate rules are wrong, and why the court should hold off its decision indefinitely while it moves forward with the repeal of the Clean Power Plan.

"Indeed, Administrator Scott Pruitt's new proposal for total repeal of the Clean Power Plan — leaving Clean Air Act duties unfulfilled and the public unprotected — only underscores why abeyance is inappropriate, especially given that the rationale for the proposed repeal tracks the statutory authority argument presented in petitioners' briefs and oral argument," according to Tuesday's brief from the groups.

"If the court nevertheless decides to place the case in further abeyance, it should do so for no longer than 120 days and it should require EPA to continue submitting status reports every 30 days," the groups added.

Tuesday's response by the environmentalists marks the beginning of what is expected to a protracted court fight well into next year and potentially beyond. The Supreme Court has halted the climate rules until the litigation has moved through the courts.

The Clean Power Plan directs each state to cut greenhouse gas emissions a third by 2030. The nearly 30 states that argued against the plan said it overstepped the EPA's authority by using a section of the Clean Air Act intended to regulate only power plants, not states.

The EPA proposed to repeal the plan last week by starting a 60-day comment period on the move. The comment period won't begin until the EPA publishes the proposed repeal in the Federal Register.

Once the comment period is over, and assuming the EPA doesn't reverse its decision to repeal, environmental groups and states that support the plan can sue the Trump EPA. If the D.C. Circuit does rule, it would throw a curve ball into the repeal process. However, it could help Pruitt strengthen his case if the court supports some part of the opponents' case.