President Donald Trump signed a bill March 12 permanently reauthorizing the Land and Water Conservation Fund and designating several million acres of new public lands and waters.

The measure, S. 47, cleared Congress in February and includes language to extend the $900-million-a-year Land and Water Conservation Fund, which is largely financed from receipts from oil and gas drilling along the Outer Continental Shelf. In signing the law, Trump issued a signing statement suggesting two relatively modest provisions raised some...