Shortly after the networks called the 2020 presidential race for Joe Biden, a list of four priorities appeared on the president-elect’s transition website. Certain observers noticed a common thread — an undercurrent, if you will — that knitted these priorities together: water. Water, which washes hands during the pandemic. Water, which is needed for factories to produce goods, farms to grow crops, and cities to reboot. Water, which has sometimes been denied to communities of color or delivered in polluted form. And water, which is how a warming planet will wreak much of its havoc.