These fears are hogwash.

Unlike many wealthy nations that will see their populations stabilize or decrease in coming decades, the United States, the world’s third most populous country, is expected to grow — to to 420.3 million by 2060 from 315.7 million people today. Our fertility rate (1.9 births per woman, slightly below the “replacement rate” of 2.1) has dipped since the Great Recession but is still among the highest of rich countries’ and ties or exceeds fertility rates in middle-income countries like Brazil, Iran, Thailand and Vietnam.

It was conservatives who largely invented the “aging crisis,” during their 1970s ascendancy. Postwar prosperity had lifted life expectancy, and birthrates had fallen from their record highs during the baby boom, but conservatives exaggerated these trends to call for welfare state retrenchment: reductions in Social Security and Medicare benefits. Meanwhile, corporations backed the last successful immigration overhaul, in 1986, for the reasons they do now: their desire for a large supply of low-wage labor.

The proposed solution to the fabricated fertility crisis — more babies — helped bury the movement for “zero population growth” that environmental activists advocated in the late 1960s and early 1970s. After Roe v. Wade (1973), support for a smaller, or at least constant, American (and global) population withered. Conservatives feared losing credibility on their staunch opposition to abortion, while liberals feared being branded anti-immigrant, particularly as Hispanics and Asian-Americans began voting heavily for Democratic candidates.

Conservatives and liberals alike generally assume that population growth drives economic growth. But until the triumph of the new laissez-faire economics in the 1970s and 1980s, most economists agreed that what mattered was not the size of a population but its human capital and its savings, investment and consumption practices. Indeed, many mainstream economists argued that a smaller but more productive population would enhance growth and lead to a more just society. It is strange that we talk on one hand about an innovation- and knowledge-based economy while still thinking about economic growth in terms of sheer body count. Moderate levels of immigration can help us maintain a highly skilled work force, but so, too, can investing more in educating our young.

Environmentalists need the courage to discuss national population growth. They would be harkening back to a bipartisan tradition, one that cites not only air and water pollution but also quality of life: recreational access to open space and our duty to protect wilderness.