BOISE - A national angling group and the state's biggest conservation organization are throwing their support behind the federal rule for managing millions of acres of Idaho's roadless backcountry.

Trout Unlimited and the Idaho Conservation League joined forces Friday to file a friend-of-the-court brief in a federal lawsuit seeking to block the Idaho roadless rule.

The federal rule was finalized in 2008 after years of public meetings and legal wrangling over how best to manage 9.3 million acres of federal backcountry across the state. The rule protects a large swath of those roadless acres but also allows logging in North Idaho, mining development in southeast Idaho's phosphate patch and other uses in some areas.

Opposition to the rule and the way it was written prompted a coalition of national and regional environmental groups to file a lawsuit last year in federal court. Lawyers on both sides are exchanging legal briefs before a hearing scheduled this fall.

Rick Johnson, executive director of the Idaho Conservation League, said his group wanted to show its backing for a policy developed by a variety of Idaho groups and interests that helps deal with the bigger challenge of managing roadless areas nationwide.

"We feel it strikes a fair balance," Johnson said. "The rule recognizes the importance of these areas for clean water, wildlife and recreation and also recognizes the needs of local communities."

The state of Idaho, Kootenai Tribes of Idaho and the Idaho Association of Counties have also joined lawsuit as interveners in defense of the Idaho rule.

The rule is the culmination of a policy debate ignited when the Clinton administration issued a rule in 2001 that banned road-building and logging on more than 58 million acres of remote national forest lands, with most of those acres in western states.

That rule was hailed by environmental groups like the Wilderness Society and Sierra Club, and denounced by industry groups. The Bush administration repealed the rule in 2005, clearing the way for states to petition the government with their own strategy for managing federal roadless areas within their borders.

Idaho was the first to present a plan, crafted by former Gov. Jim Risch after more than a dozen community meetings in cities and towns across the state.

The Idaho rule was vetted by a federal advisory panel, which included Chris Wood, the president of Trout Unlimited. Wood also was a part of the team who helped write the Clinton roadless policy when he worked for the National Forest Service.

"The Idaho rule is a demonstration of what can happen when common sense is applied to a common problem for the common good," Wood said.

Yet the rule was approved over the protests of environmentalists who oppose using a state-by-state strategy for a complex issue like national forest policy. Groups including the Wilderness Society, Sierra Club and Greater Yellowstone Coalition also claim the Idaho rule opens too many acres to industry development.

"We just don't think a state approach is going to lead to good, consistent management, any more than having a state-by-state system for running the national parks," said Craig Gehrke, regional director for the Wilderness Society. "Simply put, we have less protection with the Idaho rule than under the Clinton rule."