In a move that surprises absolutely no one who has been watching the Colorado River slowly shrink like a forgotten puddle, Arizona has officially joined Nevada's legal fight against the Trump administration's proposed cuts to their water shares. Because when diplomacy fails, litigation is the next best thing - especially when the stakes are a river that's been overused and climate-changed into a shadow of its former self.

The interior department announced this summer that restrictions could slash water supplied to the lower basin states - Arizona, California, and Nevada - over the next two years, depending on how the river is feeling that day. The river's major reservoirs, Lake Mead and Lake Powell, have plummeted to historically low levels, thanks to overuse and a changing climate. So, you know, business as usual.

The states sharing the waterway were at an impasse, with upper basin states arguing that their downstream counterparts were responsible for the shortages and should therefore face the largest cuts. The federal government stepped in after the states missed several deadlines for a consensus - because why agree when you can litigate?

The looming fear is the so-called 'deadpool' - the point at which reservoir levels plunge so far that the waterway effectively cannot flow downstream. The upper basin states - Wyoming, Colorado, Utah, and New Mexico - were spared from the water cuts, an exemption that has drawn sharp rebuke from lower basin leaders. 'We are drawing a line in the sand,' Arizona governor Katie Hobbs said in a Friday statement. 'I am taking this legal action alongside Nevada because the federal government refuses to hold the Upper Basin accountable for the water deliveries they owe Arizona, and is threatening to force draconian cuts that go well beyond the Lower Basin Agreement.' That agreement, by the way, is a two-year voluntary water conservation pact among Arizona, California, and Nevada - because nothing says 'voluntary' like a lawsuit.

Tom Buschatzke, director of Arizona's water department, added that 'intervention in the Nevada lawsuit is necessary at this time for Arizona to protect its legal rights to Colorado River water while preserving a path forward to achieving a collaborative outcome with California and Nevada to protect the Colorado River system.' In other words: we're suing, but we'd love to collaborate. An interior department spokesperson did not immediately respond to a request for comment on the joint litigation - perhaps they were busy checking the reservoir levels.