[Re: Nevada Dem Dispute] The trouble began brewing weeks earlier, when the executive board of the Nevada Democratic National Committee, in the wake of Sanders' win in the state's county caucuses in April, passed a set of new temporary convention rules (pdf) that awarded convention chair Roberta Lange, a Clinton supporter, nearly unilateral control over convention proceedings than the chair had held at prior conventions. There was no venue to challenge Lange's decisions under the new rules.

Source: “When the System Feels Rigged, How Surprising is Convention Mayhem?” Nike Knight, staff writer. CommonDreams website