Williams Cos. Inc.’s (NYSE: WMB) long-delayed Constitution natural gas pipeline from Pennsylvania to New York got another possible lifeline toward being approved after a U.S. court on Feb. 28 allowed federal energy regulators to give the project another look.

Constitution has been stuck in a nationwide battle between energy companies—who want more gas pipelines to fuel power plants and heat homes—and environmental groups and New York Gov. Andrew Cuomo, who want greater reliance on energy efficiency and renewables.

The U.S. Federal Energy Regulatory Commission (FERC) approved construction of Constitution in December 2014 pending other regulatory approval, including water quality certification from the New York Department of Environmental Conservation (DEC).

Williams applied for certification in August 2013 but withdrew and resubmitted that application twice, both times at the DEC’s request. The DEC ultimately denied Constitution’s application in April 2016.

Williams has argued to FERC and in federal courts all the way to the Supreme Court that the state waived its right to decide on the certificate by failing to act in a reasonable amount of time.

In other cases, FERC and the courts have ruled that a state must decide on a certificate within a year but have said that because Williams voluntarily withdrew its application, that one-year period did not count.

That was before the U.S. Court of Appeals for the District of Columbia Circuit in January 2019 ruled in another case, Hoopa Valley Tribe vs. FERC, the state must still act within a reasonable amount of time even though the parties agreed to withdraw and resubmit an application.

After the court’s decision in the Hoopa case, FERC asked the D.C. Circuit to remand the Constitution case back to FERC for further proceedings. The court granted that request on Feb. 28.

Officials at the DEC were not immediately available for comment.

In addition to FERC, there may be another path to get Constitution built.

President Donald Trump’s administration, which wants more pipelines built to create jobs and boost economic growth, has warned that the federal government could overturn state decisions that block projects, citing national security reasons.

When Williams proposed Constitution in 2013, it estimated the project would cost about $683 million and enter service in 2016. Delays, however, have boosted that estimate to as high as $875 million, according to local newspapers.

Constitution is owned by subsidiaries of Williams, Cabot Oil & Gas, Duke Energy and AltaGas Ltd.