The two teams of states battling over the Colorado River are nearing the end of a game they might both lose. Now, one of them is calling for last-minute, third-party intervention. In a Thursday joint statement, the Upper Colorado River Basin states of Colorado, Utah, New Mexico and Wyoming called for “immediate mediation” in the yearslong deadlock with the Lower Colorado River Basin states of Nevada, California and Arizona. They offered no details about who could fill that role or which entity would pay for the costs. “Time is short, but structured negotiations through mediation offer a new path for authentic discussions,” New Mexico’s Upper Colorado River Commissioner Estevan López said in a statement. “Even at this late stage, we should pursue every opportunity to reach a workable agreement.” John Entsminger, general manager of the Southern Nevada Water Authority and the state’s Colorado River negotiator, said in a Tuesday interview that he is ambivalent about the idea but is willing to try it.…