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

U.S. President Donald Trump said on Tuesday he will issue an executive order to increase the availability of water in California, following disastrous wildfires that recently tore through several Los Angeles neighborhoods.