Trump is taking aim at water supplies for an endangered fish, but scientists say he’s missing the point. It’s one of California’s thorniest problems. The nation’s most populous state is full of sprawling cities, vast farmland, rich ecosystems — and it must decide how to divide scarce water resources among them.

A Trump administration memo calls on the Secretary of Commerce and the Secretary of the Interior to develop a new plan within 90 days “to route more water from the Sacramento-San Joaquin Delta to other parts of the state for use by the people there who desperately need a reliable water supply.

A Trump executive order directs agencies to “to route more water” across the state. But pumping water out of the Delta has already proven disastrous.