Policymakers, politicians, and the media have been talking about the need for better water policy in the desert southwest of the United States for decades. As the Colorado River, a major source of water for much of that area, continues to shrink, policymakers are having a hard time keeping up with nature. A new 10-year plan contemplates cutting water supplies for Arizona, Nevada, and California by up to 40 percent, depending on availability. Not surprisingly, these states don't like the plan that the Trump Administration said it will impose on…