The Hopi Tribe has followed up on a threat to sue the city of Flagstaff for maintaining a contract to sell treated wastewater for snowmaking at an Arizona ski resort.

Hopis have voted down a proposed constitution that would have made sweeping changes to their tribal government.

Members of the Hopi Tribe are voting Thursday on whether to approve proposed changes to their constitution.

A tribal government in Arizona has stepped up lobbying efforts against rules being proposed by the Environmental Protection Agency that threaten the closure of a power plant. This time, the tribe is reaching out to state lawmakers.

The Hopi and Navajo nations have become central figures in a spat between two quarrelling political groups, the Sierra Club and Arizona Republican Party. Conflicting reports from the political organizations painted the picture in different ways. A Republican news release claimed that the Sierra Club was asked to leave the tribal nations, while the Sierra Club maintained that they are continuing to work with both tribes.