FROM its earliest days, the environmental movement in the United States has been animated by competing visions. In the 19th century, it was the clashing approaches of Gifford Pinchot, the founder of the US Forest Service, and John Muir, the founder of the Sierra Club. Pinchot supported "wise use" policies, believing in protecting the wilderness as well as mining natural resources. Muir was a "pure conservationist", a believer in environmental preservation.

Muir led the Sierra Club to significant victories. In the 1890s and early 1900s, the Sierra Club succeeded in expanding significantly the reach of the gigantic Yosemite National Park in California. An important component of Muir"s success in this campaign was enlisting the support of president Theodore Roosevelt during a camping trip in Yosemite.

However, the Yosemite campaign was tainted by the passage in 1913 of a bill allowing San Francisco to build a dam within the confines of the park, which Muir stridently opposed. But not all members of the Sierra Club agreed with him. Though Muir ultimately won the battle within the Sierra Club, he lost the political fight.

The Sierra Club was involved in several efforts to preserve park areas but did not again achieve national prominence until the mid-"50s and "60s, when it operated under the leadership of the energetic and aggressive David Brower.

Brower led several successful militant campaigns against dam projects in the western states, including one that would have flooded the Grand Canyon. Brower and his associates introduced the notion of "advocacy advertising", taking out full-page advertisements in major newspapers. The Sierra Club"s new dramatic style attracted broad support: in the midst of the 1960s Grand Canyon campaign, its membership doubled from 39,000 to 78,000.

But Brower"s confrontational, trigger-happy style antagonised important members of the organisation, as did his lack of attention to financial matters and in 1969, he was pushed out as executive director.

The year 1970 saw the first Earth Day and the passage of the National Environmental Policy Act, marking the beginning of the modern phase of US environmentalism. National concern for the environment mushroomed and the Club"s membership topped 100,000.

Rooted in the intellectual framework of Rachel Carson"s Silent Spring, many of the new environmentalists focused not so much on questions of environmental protection as on issues of public health. Although the Sierra Club embraced this new approach as well, it maintained its primary commitment to preservation.

On all issues, the Club coordinated its activities with other environmental groups working for common goals. There are now at least 11 major environmental organisations in the US, ranging from the National Wildlife Federation and the World Wide Fund for Nature on the right to Friends of the Earth and Greenpeace on the left.

Although its approach varies by issue, the Sierra Club leans towards the more militant and progressive pole of this spectrum. Club media director Roni Lieberman characterises the organisation as "mainstream on the cutting edge".

Ten of these mega-NGOs, excluding Greenpeace, are grouped together as the Big Ten. But the grouping has come under sharp attack for neglecting grassroots concerns, being overly willing to compromise, too concerned with maintaining good relations with politicians, and devoted to a failed strategy of controlling pollution rather than preventing it. The Sierra Club survives these charges better than most.

The Club"s broad policy is outlined by a 15-member volunteer elected board; separate committees set policy in different issue areas. Although staff members exert a strong influence over the process, the Club"s structure probably forces more accountability than is present in other big environmental organisations.

More important are its chapter structure and the fact that the Sierra Club has a genuine, involved membership. Most members of other groups are really just donors, whereas Sierra Club members are involved actively in the organisation. Individual chapters have a high degree of autonomy and participate actively in local, regional and sometimes national campaigns. This means there is a countervailing force to the staff within the organisation.

A contentious issue over the past five years has been logging in the government-owned forests in the northwest. The Washington and Oregon state Sierra Club chapters support some logging to protect jobs and the national organisation, too, is willing to negotiate compromise forest protection agreements. But other state chapters vociferously oppose any compromise efforts. Prompted by such disputes, dissident members have formed their own caucus, the Association of Sierra Club Members for Environmental Ethics. Too much emphasis on lobbying, the dissidents say, has corrupted the leadership"s vision: they demand that the Club adopt a more uncompromising line.

The Club"s official posture to the dissidents is benign. "With 500,000 members, we"re bound to have differences of opinion," says Lieberman. "We are run like a democracy and we believe everyone should have their say." In other organisations, dissatisfied members would have no option but to stop contributing money to the groups and there would be no prospect of influencing policies.

The Sierra Club does not always follow the compromise route. Only the Sierra Club and the Friends of the Earth among the Big Ten opposed the passage of the North American Free Trade Agreement (NAFTA).

So, what characteristic represents the true Sierra Club: the compromiser or the hardline opponent? Has it maintained a commitment to Muir"s preservationist ethic or has it gradually adopted a "wise-use" perspective? Will the group be defined by its insider influence or its grassroots energy?

The organisation"s self-characterisation as "mainstream on the cutting edge" suggests it does not want to answer these questions, except to the extent that it can say, "Both." Whether this balancing act can be maintained will be tested in the years to come.

The Sierra Club"s statement of purpose:
"To explore, enjoy and protect the wild places of the earth; to practise and promote the responsible use of the earth"s ecosystems and resources; to educate and enlist humanity to protect and restore the quality of the natural and human environment; and to use all lawful means to carry out these objectives."