President Donald Trump reinstated an executive order Monday barring US foreign aid from going to any nongovernmental organization (NGO) that either provides abortion services, or even discusses abortion with its patients as an option for family planning.

A statement from Population Action International (PAI), a global family planning advocacy organization, called the move to reinstate the so-called global gag rule, “the beginning of the Trump-Pence administration’s agenda to punish women everywhere.”

Trump has promised to take sweeping actions against abortion, including appointing Supreme Court justices who would overturn Roe v. Wade. Reinstating the global gag rule is the first indication of how serious he is.

The global gag rule has become something of a political seesaw since Ronald Reagan first implemented it in 1984 at a United Nations population conference in Mexico City (which is why it’s also called the “Mexico City policy”). Bill Clinton repealed it immediately when he took office. George W. Bush immediately reinstated it when he took office. Then Barack Obama immediately repealed.

But the effects of reinstating the gag rule now — especially after eight years of the Obama administration, which supported sexual and reproductive health in foreign aid — will be nothing like a seesaw. It will be very messy, advocates say, with ripple effects and unintended consequences that will have devastating effects on the health of women and girls around the globe. And while it will export the US abortion wars overseas, only foreign women will be the casualties.

“Trump’s global gag rule will obstruct and destroy the work of health care providers who are often women’s main — and sometimes only — source for reproductive health care, and their entry point for receiving a wide range of primary health care services,” said Suzanne Ehlers, president and CEO of PAI, in a statement.

The gag rule does wide-ranging damage to women’s health abroad

The global gag rule goes much further than simply banning US foreign aid from paying for abortions directly — which is already the law, and which has its own detrimental consequences for women.

Instead, the gag rule tries to control how international organizations use their own funds, raised from other sources. Just like Republican efforts to defund Planned Parenthood in the United States, it’s an attempt to stop abortion from happening by forcing organizations that provide it to make a choice: stop providing or promoting abortion, or lose the large amounts of funding that you get from the US government to support your other medical services.

The reality is simple and brutal. Reinstating the global gag rule will not reduce abortions. Sub-Saharan Africa, for instance, had higher abortion rates after George W. Bush reinstated the gag rule, because it reduced women’s access to contraception and caused more unwanted pregnancies, which women then chose to terminate.

The gag rule will, however, lead to more women dying across the developing world. Marie Stopes International, a major global family planning organization, estimates that without alternative funding, the loss of its services alone will cause 6.5 million unintended pregnancies, 2.2 million abortions, 2.1 million unsafe abortions, and 21,700 maternal deaths just in Trump’s first term, from 2017 to 2020. The organization says it will also be prevented from reaching 1.5 million women with contraception every year.

Studies conducted by PAI have shown that every time the global gag rule returns, more women in developing countries bear unwanted pregnancies, die or become disabled due to unsafe abortions, or lose crucial medical care.

Large international family planning organizations like Marie Stopes International and the International Planned Parenthood Federation have been able to bring crucial contraceptive services to areas like West Africa that were poorly served before, PAI director of advocacy Jonathan Rucks said. With the gag rule back in effect, large geographic areas may simply lose services, including birth control.

That’s because those large organizations aren’t going to simply stop offering abortion care or counseling worldwide, and so they will lose USAID (United States Agency for International Development) funding as a result.

“Marie Stopes International knows that safe abortion is a vital component of women’s reproductive healthcare, and therefore we cannot agree to these conditions,” read a statement from the organization in response to Trump’s executive order.

The gag rule hurts not just abortion access, not just contraception access, but other forms of health care as well, Rucks said. In many developing countries, women get reproductive health care at the same place they get all of their other care. So when health care providers lose funds due to the gag rule, it slashes funding and causes nurses to be laid off for all health care services the provider offers.

And the rule has both direct and indirect consequences, Rucks told Vox. Because the Obama administration had such supportive sexual and reproductive health policies, the United States was able to partner with other donor governments, like the United Kingdom and Sweden, that also support reproductive freedom. But those governments “won't be as likely to want to pool funds with us” for international aid if the Trump administration implements such negative and harmful policies, Rucks said.

The gag rule isn’t the only US policy that has this overall effect. But it has earned a reputation among human rights advocates as a particularly cruel, draconian measure that exists for one purpose only: appeasing far-right opponents of legal abortion in the United States.