California’s offer to conserve some of its share of Colorado River water over the next few years won’t solve the looming water and power crisis in the West — but it might be enough to kickstart negotiations among the states on a deal that could.

The biggest hurdle to striking an agreement that would sharply curtail water use among the seven states that share the river has been the impasse between the two thirstiest states — California and Arizona — over which should shoulder the brunt of the cuts as climate change fuels the deepest drought in the region in 1,200 years.