Frustrated with the government shutdown and Republican shenanigans on the healthcare law? You might want to go back a few decades and blame Henry Hyde, a representative from Illinois, and his conservative cohorts in Congress. They were the lawmakers who laid the groundwork for congressmen denying healthcare based on ideology and political whims, and their insistence that your care reflect their moral values shapes political battles – and your rights – today.

Thirty-seven years ago this week, the Hyde amendment was first attached to an appropriations bill. It banned any federal funding of abortion by outlawing it in the Medicaid program. Since 1976, Hyde has been reauthorized again and again. Women's health groups routinely oppose it, even bringing and losing a Supreme Court case over it.

President Clinton managed to get an exception for rape and incest into the amendment in the 1990s. But today, outside of the civil liberties organizations and women's advocacy groups that are still pointing out the harms wrought by Hyde, there's little mainstream political will to seriously challenge the law, even within the Democratic party. That Democrats so easily backed down on the Hyde amendment is a real shame, because that cowardice handed the GOP an effective road map for denying healthcare coverage for people or procedures they dislike.

Medicaid and Medicare provide healthcare to low-income, elderly and vulnerable Americans, and are some of the most popular social welfare programs in the United States. They passed thanks to liberal control of Congress in the mid-1960s. But after the Supreme Court decided Roe v Wade – initially to little fanfare – in 1973, extending the right to abortion to all American women, conservatives adopted an anti-abortion position as part of its efforts to solidify a base of segregationists, newly politicized religious Christians, and other traditionalists increasingly wary of rapidly-shifting social mores around race and gender.

Enter Henry Hyde, a right-wing senator from the suburbs of Chicago, Illinois for whom abortion was a personal obsession. Realizing he couldn't deny the right to abortion to all American women, Hyde targeted the ones he could: low-income women relying on Medicaid. The initial iteration of the Hyde amendment barred Medicaid funding for any abortion, including cases of rape or incest, even to save the pregnant woman's life. In the years following, more progressive lawmakers managed to add in rape, incest and threat-to-life exceptions, and some individual states decided to pay for abortion care with their own funds. But Democrats were never able to do away with the amendment itself, and today it's far from the top of the party's priority list.

Today reproductive healthcare for low-income women is in crisis. The US has one of the highest unintended pregnancy rates among developed nations, and one of the highest maternal mortality rates. Women are more likely to die during childbirth in Republican-dominated states than in more liberal ones, and poor women are particularly vulnerable. Many pregnant women find themselves pawning their valuables in order to pay for an abortion, or begging family and friends for money.

Barriers to abortion access – Hyde premiere among them – mean that low-income women often end up having abortions later in the pregnancy than they otherwise would have, which means the procedure is more expensive and more difficult to obtain. Organizations like the National Network of Abortion Funds have sprung up to fill the gap, but they can't meet 100% of the need.

Hyde also means that some low-income women who want to terminate their pregnancies aren't able to get abortions at all. Those women, of course, adjust to their life circumstances as all of us do, but they are much more likely to suffer negative health and financial consequences than similarly-situated women who were able to terminate. Even when previous financial differences are taken into account, women who sought to have abortions but couldn't are three times as likely to fall below the federal poverty line two years after giving birth.

The takeaway from Hyde should be that denying low-income people healthcare is a public health disaster, and no one should be refused a necessary and legal medical procedure because of their income. But, the GOP learned that Democrats will fold on basic rights if it only impacts poor women, and if they can isolate particular aspects of medical care that a large enough segment of the population feels morally superior about. One in three American women will have an abortion in her life, but the GOP managed to turn terminating a pregnancy into a divisive issue where half the American public thinks the government should have control.

The Hyde amendment led to the passage of several similar laws restricting abortion access for government employees, military families, Indian Health Service clients, federal prisoners and Peace Corps volunteers, all of whom must pay for abortion coverage out of pocket despite ostensibly having health insurance. Ronald Regan passed the Mexico City Policy, now better known as the Global Gag Rule, which defunds any US organization abroad that so much as mentions abortion as an option or promotes abortion rights. The gag rule is a tireless political football, repealed by Democratic presidents and reinstated by Republican ones.

Conservative lawmakers have also successfully promoted "conscience clause" legislation, allowing healthcare providers to refuse to do their jobs if they hold religious beliefs that conflict with offering care. Of course, the "religious beliefs" are typically extreme Christian ones – doctors and pharmacists may refuse to give the morning-after pill to a rape victim and emergency rooms at Catholic hospitals can refuse to effectively terminate life-threatening ectopic pregnancies, but you'll be hard-pressed to find a hospital that would allow an Orthodox Jewish or conservative Muslim male ER doctor to simply refuse to touch female patients. In fact, you'll be hard-pressed to find many "conscience clause" exceptions that don't involve religious zealots deciding it's their business to meddle in what you do with your private parts.

More recently, the Stupak amendment picked up where Hyde left off, prohibiting Affordable Care Act funds not only from paying for abortion procedures, but from going to any healthcare plan that independently covered abortion care. The sponsor of that bill, by the way, was Bart Stupak of Michigan, a Democrat. His amendment didn't make it to the version of the bill passed by the Senate, but in order to secure the votes of conservative Democrats, President Obama pledged that Hyde would extend to his healthcare law. Republicans also largely opposed including coverage of contraception in the ACA, demanding accommodations for employers who think it's their business to determine if their employees use the pill. The Obama administration again made concessions, crafting an elaborate provision that allows religious organizations to avoid funding medical care that conflicts with their morals.

The healthcare plan went into effect on 1 October. In order to derail it, Republicans have forced a government shutdown. They've collectively decided that despite legislative defeats, they have a mandate to deny Americans – disproportionately lower-income Americans – healthcare. And to meet it, they'll throw a temper tantrum that not only means federal workers aren't getting paid, but people who rely on federal benefits (disproportionately lower-income Americans, disproportionately women and children) will have to do without. Notice a pattern?

Democrats should have drawn a line in the sand in the 1970s: conservatives don't get to target poor women and deny them medical care. Instead, we've lived with the Hyde amendment for 37 years, and Democrats continue to make deals with conservatives if all they have to give up is poor women's health. Today, perhaps we should take note of just how long and wide the shadow of Hyde has spread.