CHEYENNE, Wyo. (AP) — Wyoming Gov. Mark Gordon vetoed a bill Friday that would have allowed the Legislature to sue the state of Washington over coal exports.

It's important for Wyoming to "speak with one voice" on coal-export litigation, Gordon said.

Wyoming is the top coal-producing state. Wyoming's coal industry seeks to export more coal overseas to offset declining demand for coal from electric utilities in the U.S.

A developer is suing Washington state for denying a crucial permit for a $680 million coal-export facility. Wyoming and five other states — Kansas, Montana, Nebraska, South Dakota and Utah — have filed friend-of-the-court briefs siding with the developer.

Six states — California, Maryland, New Jersey, New York, Massachusetts and Oregon — have filed a friend-of-the-court brief backing Democratic Washington Gov. Jay Inslee's administration.

Wyoming lawmakers argued that a friend-of-the-court brief doesn't go far enough and Wyoming should file its own lawsuit. The bill would have authorized legislators in the months ahead to look into filing their own lawsuit.

A lawsuit from Wyoming's legislative branch threatened to introduce a "whole new set of topics" and delay the case, said Gordon.

"We just wanted to make sure we have a coherent approach that wasn't confusing," Gordon said.

Gordon said he would continue to discuss with Wyoming Attorney Bridget Hill, an appointee of his who was sworn in Friday, how to best approach the litigation.

Gordon and a substantial majority of the Wyoming Legislature are Republicans.

"It's going to take a team effort between the executive and legislative branches for there to be success on this issue," bill co-sponsor Rep. Chuck Gray, R-Casper, said in statement. "This bill created a framework for this team effort to occur, so that we have the best chance for success on this issue. The veto is detrimental to that effort."