Well, that was quick.

On his third day in office, Trump showed his hand on female reproductive rights (not like we didnt already know…) He moved to block U.S. aid for organizations that “promote” abortion. In this case, “promoting” abortion means presenting it as a viable option and/or providing abortion counseling.

Similar rules have been in place since 1984, when President Ronald Reagan instituted the first rule known as the Mexico City policy. (The policy was named for the location in which Reagan announced it.) Depending on which party is in office, the bill has been repealed (by Bill Clinton and Barack Obama) and reinstated (by George H. W. Bush and George W. Bush).

Despite the fact that the policy has been around for over 30 years, it’s unclear whether it’s actually working:

Health experts say the policy has not led to a decline in abortions in the affected countries. Some research suggests that it has had the opposite effect: increasing abortion rates by forcing health clinics to close or to restrict contraceptive supplies because of lack of funding. Others say the restriction only heightens the risk of illegal and often unsafe abortions.

A study completed by the Stanford University School of Medicine in 2011 found that the Mexico City policy was “linked to increases in abortion rates in sub-Saharan African countries.” But the study also found that it was difficult to link a country’s abortion rates back to the policy.