A federal judge in South Carolina on Thursday blocked the Trump administration from delaying enforcement of a controversial Obama-era definition of what constitutes Waters of the United States (WOTUS), issuing an injunction making the rule law in 26 states where the 2015 Clean Water Rule (CWR) has not already been stayed.

In a motion for summary judgment brought by a coalition of conservation groups, Judge David C. Norton of the U.S. District Court for the District of South Carolina in Charleston found that the federal government failed to comply with the requirements of the Administrative Procedure Act (APA) in implementing the Suspension Rule, a two-year delay of the CWR enacted in February by the Environmental Protection Agency (EPA) and Army Corps of Engineers.

The environmental groups had argued that EPA and the Army Corps violated the APA by taking action with inadequate public notice and comment, failing to consider the substantive implications of suspending the rule, and failing to restore to the Federal Register the 1980s regulation WOTUS was meant to replace.

“As administrations change, so do regulatory priorities,” Norton wrote in an 18-page order. “But the requirements of the APA remain the same.”

The order granted summary judgment to the coalition and enjoined the Suspension Rule nationwide.

Reinstatement of the CWR may not be long lasting. Last month, EPA and the Army Corps said they plan to repeal the CWR, rather than modify it, arguing that the definition has led to regulatory uncertainty and runs afoul of previous rulings by the Supreme Court.

Controversy surrounded the CWR since it was unveiled by the Obama administration in May 2015. The rule was opposed from the start by the oil and gas industry, agricultural interests, manufacturers and their Republican allies in Congress. At the time, the EPA and the Army Corps called the rule an “historic step” to protect clean water from pollution and degradation in streams and wetlands throughout the nation that would more “precisely define” the protected waters.

According to the EPA, the proposed WOTUS definition would include all territorial seas, interstate waters and wetlands and all waters that are currently being used — or which were used in the past or which may be susceptible for use in interstate or foreign commerce — including all waters subject to the ebb and flow of the tide. It also includes certain impoundments, tributaries and adjacent waters, including wetlands.

Opponents of the rule said it had been interpreted to include ditches and ruts in dirt roads that captured rainwater.

The U.S. Court of Appeals for the Sixth Circuit issued a stay on the CWR in October 2015.

Trump has characterized the CWR as an example of federal regulatory overreach.