Just because abortion is legal in the U.S. doesn’t mean all women have access to it. We’ve heard stories of women traveling hundreds of miles, sometimes across state lines, to reach the nearest clinic. Then there’s the Hyde Amendment. Never heard of it? That’s the problem.

Forty years ago last week Congress tacked the amendment onto an appropriations bill. It prevents Medicaid from paying for abortions, except in cases of rape or incest, or situations where the pregnancy puts the life of the mother at risk.

Medicaid provides healthcare for low-income Americans, and it serves a disproportionate number of minorities. These women are eligible for government-supported healthcare specifically because they can’t afford it and don’t have access to health insurance through an employer. So it shouldn’t be surprising that one in four women on Medicaid seeking an abortion ends up carrying her pregnancy to term.

The crazy thing is Medicaid provides women access to other sexual health services, including sterilization and birth control. In many states, it will cover the cost of Viagra for men. But when it comes to abortion, women don’t have a choice (unless they can pay for it out of pocket).

The upcoming election could change that: Hillary Clinton has said she’ll fight to repeal the Hyde Amendment, while Donald Trump is a firm supporter of the policy.