The vast Colorado River, recently in the news over a troubled drought deal, is at the heart of numerous environmental problems in the American West, where water is scarce and the legal complexities of water rights voluminous. The latest Issue Backgrounder offers an explainer on the story, which involves at least seven states, the federal government, Native American tribes, a hornet’s nest of irrigation districts and even Mexico.

The fierce contest over the Trump border wall has critical environmental implications, both local and regional, per the latest TipSheet. A key suit against the Trump emergency declaration was filed by environmental groups and plans for a border barrier may harm significant wildlife habitat, as well as numerous migrating species, including some that are endangered. Get the back story and why it matters, along with story ideas and reporting resources.

U.S. courts will be a key venue of environmental conflict in 2019, as the Trump administration pushes back against an extensive array of long-standing environmental law. This special edition Issue Backgrounder looks at seven key legal disputes, including cases involving climate change liability, intergenerational equity and policy, as well as conflicts over maintaining national monuments, defining which waters are subject to anti-pollution rules, disposing of coal ash and extending offshore drilling.