Sen. Bernie Sanders (I-Vt.) was asked to weigh in on an issue Wednesday that hasn’t really penetrated the 2020 presidential race to date: global population control. But his answer rekindles a decades-old debate.

During CNN’s climate change town halls Wednesday night, a teacher named Martha Readyoff asked Sanders if he would support making population control part of his climate-change agenda. And Sanders said he would:

READYOFF: Good evening. Human population growth has more than doubled in the past 50 years. The planet cannot sustain this growth. I realize this is a poisonous topic for politicians, but it’s crucial to face. Empowering women and educating everyone on the need to curb population growth seems a reasonable campaign to enact. Would you be courageous enough to discuss this issue and make it a key feature of a plan to address climate catastrophe?
SANDERS: Well, Martha, the answer is yes. And the answer has everything to do with the fact that women in the United States of America, by the way, have a right to control their own bodies and make reproductive decisions.
And the Mexico City agreement, which denies American aid to those organizations around the world that are — that allow women to have abortions or even get involved in birth control, to me is totally absurd. So I think, especially in poor countries around the world where women do not necessarily want to have large numbers of babies, and where they can have the opportunity through birth control to control the number of kids they have, it’s something I very, very strongly support.

Sanders’s comments drew almost instant denunciations on the right. The Republican National Committee accused Sanders of saying he wanted to “abort poor babies for population control.” Conservative CNN host S.E. Cupp accused Sanders of supporting “EUGENICS.” Fox News’s headline alleged that Sanders said “he’d back US funding for Third World abortions.”

We can say three things:

  1. Many of these critiques distort what Sanders actually said.
  2. The policy Sanders said he would reverse is something each of the past two Democratic presidents have reversed, so his position on it is hardly a surprise. And …
  3. Sanders talked about the issue in a way Democrats haven’t generally talked about it, which should raise some eyebrows.

The “Mexico City agreement” is also known as the “Mexico City policy” or the “global gag rule.” It prohibits U.S. foreign aid not just directly for abortions, but for any organization that provides abortion or abortion-related services.

The reason its name includes the Mexican capital is that it was introduced there in 1984 at a global conference on the threat of population growth. The Reagan administration caused a stir by introducing the policy and de-emphasizing the threat of overpopulation at a time when much of the world was quite concerned about the issue — hence the global conference, the first of which had been held in 1974.

Since then, the rule has been a political football, predictably being passed back and forth depending on which party wins the White House. Bill Clinton reversed it in the early days of his administration in 1993. George W. Bush reinstated it shortly after his inauguration in 2001. Then Barack Obama pulled it back in 2009. Then President Trump put it back in place in 2017.

The reason all this might be news to people is that population growth has generally moved to the back burner as a political issue — and it’s not often invoked in the U.S. climate change debate. Sanders seems to think it should be.

Back in 1984, population growth was generally talked about as an economic and political threat — and less so an environmental one. “Rapid population growth that outstrips a nation’s resources and its economy’s ability to produce jobs serves as a breeding ground for civil and political unrest,” the New York Times’s editorial board wrote in opposition to Reagan’s 1984 policy. Even Reagan’s defense secretary, Caspar Weinberger, had at a 1974 global conference endorsed family planning for developing nations to combat population growth “that makes economic development more difficult.” (Weinberger was then in the Nixon administration.)

The population growth debate has largely subsided because early projections of the amount of growth and the coinciding disasters never really panned out. Invoking this in the context of the climate change debate risks accusations of overhype and alarmism — which are already the chief arguments against immediate action on climate change. Plus, as reaction to Sanders’s response showed, abortion foes see an inherent link between population-control efforts and an uptick in abortions.

But Sanders is hardly the first Democrat to attach the issue to environmental concerns. In his 1992 book, soon-to-be Vice President Al Gore wrote, “No goal is more crucial to healing the global environment than stabilizing human population.”

Yet Democrats have also been careful to separate abortion from population control — instead arguing the Mexico City policy would hurt other efforts besides abortion, by defunding organizations that provide a variety of services.

Amid a rift with the Vatican over his reversal of the policy, for example, Clinton in 1994 declared that “the United States does not and will not support abortion as a means of birth control or population control.” The line from the Obama administration was similar, given that Obama himself had campaigned on reducing abortions, even as he supported the right to one.

It’s important to note that even reversing the Mexico City policy doesn’t mean U.S. funds can go to funding abortions. Congress in 1974 banned the use of U.S. funds for abortion and abortion-related services, and that law remains on the books. The Mexico City policy simply expanded on that to prevent the funding of groups that provide such services — even if the money doesn’t go directly to abortion services. It’s similar to the debate over Planned Parenthood, which Republicans want to defund even though the federal funding it receives is already prohibited from being used for abortion services.

Sanders’s 2016 campaign said he opposes that 1974 law, known as the Helms amendment. So it’s fair to say that he supports federal funding for foreign abortion services. (Hillary Clinton did, too.) But saying he supports that policy in order to “abort poor babies for population control" is taking things to another level. One can support federal funding for abortions domestically, for instance, without believing it should be used specifically to stop population growth.

Sanders did invoke abortion in his answer, but only in accurately describing what the Mexico City policy does. He also nodded generally to the idea that American women “have a right to control their own bodies and make reproductive decisions” as a key principal. But when describing specifically how he would support combating global population growth, Sanders only mentioned birth control. People may infer things from the fact that he invoked “reproductive decisions” in his answer, but he never said he thinks the United States should support abortion as a means of population control.

At the same time, he’s wading into an issue that is dicey. Despite its origins, the Mexico City policy isn’t generally talked about in the context of population control these days, nor is population control as frequent a climate change topic as Gore seemed to regard it in 1992. Sanders’s answer certainly invites more debate on how much of a priority this is for the Democratic Party — and what specifically should be done about it.

This post has been updated to clarify Sanders’s position on the Helms amendment.