On Monday, May 28, the Sierra Club turned 126 years old. Throughout its existence, the group's lobbying for environmental regulations has earned it a permanent place in progressive circles. But many may be surprised that the group was once a haven for immigration restrictionists.

The Club's restrictionist origins can be traced back to 1968 when it published a best-selling book titled The Population Bomb by biologist Paul R. Ehrlich. In it, Ehrlich argued that population growth was responsible for the earth's environmental decline, and advocated for immediate action in fighting against overpopulation. In the 1980s, the Sierra Club urged Congress to make population stabilization a chief US goal. A few years later the Club asserted that "Immigration to the U.S. should be no greater than that which will permit achievement of population stabilization in the U.S."

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One of the members who was influenced by Ehrlich's work was the Michigan eye doctor John Tanton. Tanton's concern about population growth's impact on the environment inspired him to serve as chairman of the Sierra Club's population stabilization committee from 1971 to 1975. In 1979, those same concerns propelled him to create the Federation for American Immigration Reform (FAIR), which would become one of the most influential US organizations advocating for less immigration.

Six years after creating FAIR, Tanton helped secure a grant that launched the Center for Immigration Studies (CIS) a think tank that describes itself as "Low immigration, Pro-immigrant." He also helped his former editor, Roy Beck, raise funds to launch NumbersUSA, a grassroots nonprofit that's also devoted to immigration reduction.

Tanton's engagement with FAIR ended when he left the advisory board in 2002, and his involvement in CIS and NumbersUSA never extended beyond his startup assistance. But some people involved in the restrictionist network are motivated by the same environmental concerns that worried Tanton. Roy Beck, for example, is a disgruntled former environmental reporter who blames poor air and water quality and a lack of open spaces on overpopulation from immigration. The Colcom Foundation, the largest funder of immigration restriction groups is animated by the same set of concerns, with their mission being to "foster a sustainable environment…by addressing the major causes and consequences of overpopulation."

Several of these environmentalists are concerned enough about overpopulation that they have outright advocated for abortion to reduce the US population size.

Several of these environmentalists are concerned enough about overpopulation that they have outright advocated for abortion to reduce the US population size. CIS Fellow David North, for example, argues that "too many people means too much pollution and not enough green space." He believes that there should be a "low-growth population organization" that seeks to "curtail needless restrictions on abortion." This is similar to the mission of the Weeden Foundation, another funder of FAIR, CIS, and NumbersUSA. The Foundation says that "an increasing population causes greater impact on the environment and loss of biodiversity" and believes that the liberalizing of Latin American abortion laws are among the "interventions necessary to lower birthrates." Tanton himself started a local Planned Parenthood Chapter in Northern Michigan for the same reasons he started FAIR.

At first glance, it's difficult to see the environmentalists in a coalition with other restrictionists. The former is comprised of a largely secular, socially liberal elite. The latter is filled with economic and cultural populists. But what they hold in common is a shared belief in a zero-sum world and an ahistorically, pessimistic outlook for what voluntary human cooperation can accomplish.

Mark Krikorian, executive director of CIS, observed in the National Review that 14 years ago there were left/right alliances on both sides of the immigration debate, and the choice was between the patriotic coalition or the post-American coalition.

American conservatism is built on the precepts that individuals are valued as ends in themselves and that public problems are best answered by civil society.

But people are defined by their own principles, not those of their coalition partners. American conservatism is built on the precepts that individuals are valued as ends in themselves and that public problems are best answered by civil society. A conservative vision for the American immigration system is one that removes barriers that impede individual choice, opportunity, and the exercise of responsibility.

Immigration restrictionists of the left and the right may have different reasons for their positions, but both are similar in that they demand the sacrifice of individual liberty in favor of centrally planned objectives.