(CNN) Former Vice President Joe Biden's complicated position on abortion took a new turn Thursday night when he announced during a Democratic National Committee event in Atlanta that he no longer supported the Hyde Amendment.

The declaration came a day after Biden's campaign had emphasized that he still supported the measure, leading to an onslaught of criticism from his fellow Democratic presidential candidates. That statement from the campaign Wednesday had come after the American Civil Liberties Union posted video of him telling a woman at a May presidential campaign event that the Hyde Amendment had to go.

Ending the Hyde Amendment is a pretty orthodox thing for a mainstream Democrat these days. It was part of the official party platform in 2016

But Biden has not been an orthodox Democrat on this issue, though he seems to be aiming for the party line now, and the Hyde Amendment is not orthodox policy.

Here's what you need to know about both Biden's position on abortion and the Hyde Amendment. Note: Much of the information in this piece comes from the Kaiser Family Foundation and the Congressional Research Service

What's the Hyde Amendment?

, as Hyde himself had had an affair decades earlier) later role in pushing for the In 1976, as Congress was passing bills to fund the government in 1977, Rep. Henry Hyde of Illinois inserted a sentence into the funding bill for the Departments of Labor and of Health, Education, and Welfare, which funds Medicaid and a lot of other things. You might also have heard of Hyde for his important (and ultimately awkwardas Hyde himself had had an affair decades earlier) later role in pushing for the impeachment of President Bill Clinton

The text of his original abortion amendment was this: "None of the funds contained in this Act shall be used to perform abortions except where the life of the mother would be endangered if the fetus were carried to term."

It essentially banned the use of federal funds for all but a small sliver of the abortions sought by people on Medicaid, who are all low-income. The original language has since been updated to include exceptions for rape and incest.

Subsequent court rulings pared back some of what the Hyde Amendment did, but its basic framework stuck. In fact, similar language has appeared in many different funding bills, which means federal funds can't be used to subsidize abortions as part of foreign aid, for instance. They also can't be used for abortions in health insurance for federal employees.

Not a permanent law

But the key to the Hyde Amendment is that it isn't permanent law. It applies only to the spending bill into which it's inserted.

That means, in a scenario where both houses of Congress were prepared to strike the language from the next year's spending bill, suddenly, federal funds could theoretically subsidize abortions again.

Efforts by Republicans to enshrine the Hyde Amendment into permanent law have failed, although one did pass the House in 2017, when Republicans still controlled that body

The Hyde Amendment and the Affordable Care Act

A fight among Democrats over language similar to the Hyde Amendment almost sank the Affordable Care Act, which some people call Obamacare. Democrats in the House inserted the language into their version of the bill in order to get Democrats who opposed abortion rights -- remember Michigan's Bart Stupak? -- to vote for the legislation. It was stripped in the Senate version that ultimately became law, so President Barack Obama signed an executive order to mollify Stupak and others. It ticked off abortion rights supporters.

The end result in the Affordable Care Act is a complicated system whereby plans subsidized under the law can cover abortions as long as the insurance company segregates the funds that cover abortion into a separate account. Some states ban coverage for abortion in subsidized plans altogether. In additional states, there are no Affordable Care Act marketplace plans that cover abortion.

Some states have their own systems

There is also a discrepancy in how certain states have applied the Hyde Amendment to Medicaid plans. According to the Kaiser Family Foundation , most states follow the Hyde Amendment and offer abortions to Medicaid recipients only in cases of rape, incest or where the woman's life is in danger. However, 15 states provide their own funding for a wider range of abortion services to Medicaid recipients.

The result, according to Kaiser, is that more than 8 million women -- more than half of the women of child bearing age on Medicaid -- do not qualify for most abortion services.

Joe Biden and the Hyde Amendment

Biden was first sworn in to the Senate in 1973, the same year the Supreme Court decided Roe v. Wade. He's a devout Catholic and he personally opposes abortion rights on religious grounds. But he's also a Democrat and he doesn't want to force his opinion on others.

"I accept my church's position on abortion as a what we call de fide doctrine. Life begins at conception. That's the church's judgment. I accept it in my personal life," he said. "But I refuse to impose it on equally devout Christians and Muslims and Jews. I just refuse to impose that on others," he said.

He added: "I do not believe that we have a right to tell other people, women, that they can't control their bodies. That's a decision between them and their doctor, in my view, and the Supreme Court, I'm not going to interfere with that."

In fact, Biden used his support for the Hyde Amendment to help sway Democrats like Stupak to support the Affordable Care Act.

Biden actually has an amendment named after him, too, which forbids federal foreign assistance for biomedical research related to abortion.

Our volunteer Nina asked Joe Biden whether, as president, he would lift the Hyde amendment, which bans federal insurance coverage of abortion.



He said yes. #RightsForAll pic.twitter.com/W4jT7RLNzN — ACLU (@ACLU) May 8, 2019

-- though the woman spoke the words "Hyde Amendment" to him twice -- and continued to support it. By Thursday night, that had changed. So it was interesting when the ACLU posted that video of a woman asking Biden if he agrees the Hyde Amendment should be struck from spending bills. He seemed to say yes, but his campaign said Wednesday that he had misheard the question though the woman spoke the words "Hyde Amendment" to him twice -- and continued to support it. By Thursday night, that had changed.

"If I believe health care is a right, as I do, I can no longer support an amendment that makes that right dependent on someone's ZIP code," he said Thursday.

This story has been updated following news on Thursday that Biden no longer supports the Hyde Amendment.