The U.S. population could hit a half-billion people by 2044, according to one Census Bureau projection, and the Sierra Club's leaders don't want to do anything about it. Worse, they don't want anyone in the club to talk about it. And any club member who defies the gag order gets pelted by charges of racism. Things have gotten nutty at the Sierra Club.

An exploding U.S. population fuels nearly every environmental crisis -- from water shortages to sprawl to loss of wildlife habitats. The Sierra Club's leadership won't touch the subject because the chief source of population growth today is immigration -- an issue that can take on racial overtones. "It is environmental malpractice to avoid this issue because it is sensitive," says former Colorado Governor Dick Lamm. Now running for the club's 15-member board, Mr. Lamm is one of three petition candidates vowing to address the population problem.

Three decades ago, the Sierra Club backed save-the-earth rallies centered on controlling population growth. Marchers waved copies of Paul Ehrlich's THE POPULATION BOMB. Environmentalists back then feared that baby boomers would do as their parents had done -- make big families. And they weren't afraid to tell middle-class Americans to have fewer children.

Now that immigration is fueling nearly all population growth, the club leadership has fallen silent. The Sierra Club leaders know that most of the members wanting to lower immigration levels are good liberals interested in numbers, not in skin color. But they lack all courage in defending them. Indeed, they join some Hispanic activists in tarring as racist anyone who challenges current immigration policy. The heaviest artillery is directed at the club's board candidates who speak hard truths on population.

"This is the toughest election that I have ever run," says Mr. Lamm, a Democrat who started his career as a civil-rights lawyer and was elected Colorado governor three times. "There is a level of vituperativeness that I never have seen."

Morris Dees, a founder of the Southern Poverty Law Foundation, has decided to join the slander brigade. Mr. Dees is issuing ludicrous warnings of a "right-wing takeover" at the Sierra Club. (He has come up with a catchy phrase that he repeats over and over: "the greening of hate".)

Past Sierra Club board elections have revealed strong support for addressing the population issue, so the smear job may not work. Indeed, three current board members have survived assassination attempts on their character and openly back establishing a serious population policy. They are: Doug LaFollette, Wisconsin's secretary of state and a Democrat; Paul Watson, co-founder of Greenpeace; and UCLA astronomer Ben Zuckerman. Hardly a cabal of cryptoracist fiends.

The basic question is whether Sierra Club members want their leaders to continue sitting on their hands as the U.S. population heads to a half-billion. That many people wouldn't tread lightly on the planet. That's what this issue is about.

Re: "Curbing growth not racist," by Froma Harrop, last Monday's Viewpoints.

The issue in the Sierra Club's upcoming board election is not whether our club should change its immigration policy, as suggested by columnist Froma Harrop. The issue is whether we are going to uphold the club's democratic policy-making process or allow our policies to be dictated by outsiders with narrow political agendas and no experience in the club.

In 1998 the members of the Sierra Club voted to adopt an immigration policy that addresses the root causes of global population growth. Those who advocated an anti-immigration position and lost have turned to outside organizations in an attempt to take over the board and force on the club a policy that its members rejected in 1998. They have recruited outsiders affiliated with anti-immigration organizations to run for the board, and they have urged members of other nonenvironmental organizations to join the Sierra Club for the purpose of voting for these single-issue candidates.

Immigration policy will again be the subject of a clubwide referendum in 2005. Those who support a change in the club's policy will rightfully have the opportunity to advocate their position to the club's membership. That's how democracy works.

The only reason this effort has a chance of succeeding is that many members fail to vote in national club elections. Sierrans who share mainstream conservation values must protect the club from extremism and ensure its continued credibility by casting an informed vote.