The state’s highest court has sided with the state Department of Environmental Protection and rejected a bid to invalidate permits at NorthPoint, a Cambridge mega-project at the center of a lengthy legal battle.

In a decision today, the Massachusetts Supreme Judicial Court backed the Legislature’s 2007 tidelands bill to issue exemptions from certain waterfront licensing regulations.

The state Department of Environmental Protection had exempted most filled tidelands from such statutes, but the SJC’s 2007 ruling found that only the Legislature could issue such exemptions. A group of Cambridge residents had challenged the validity of the 2007 tidelands bill. Today’s SJC decision puts that challenge to rest.

"Although we are not unsympathetic to the plaintiff’s view, we ultimately agree with the defendants that the act does not extinguish and relinquish public trust rights in landlocked tidelands," the decision reads.

Several deals to sell the 5 million-square-foot construction project have fallen through in the past few years.