WASHINGTON — Former Vice President Joe Biden’s decades-long evolution on abortion rights has in many ways mirrored the changing attitudes of the Democratic Party, growing increasingly supportive over time.

But his past opposition to most federal funding for abortion services is more striking than previously recognized, according to an NBC News review of his Senate voting record, and includes repeated examples of Biden rejecting exceptions for victims of rape and incest that were supported by many members of his party at the time.

As a U.S. senator from Delaware, Biden voted against a 1977 compromise that allowed Medicaid to fund abortions that included exceptions for victims of rape and incest in addition to concerns for the life of the mother. While the rape and incest exceptions passed in that case, Biden voted in 1981 to again remove them, in what was the most far-reaching ban on federal funds ever enacted by Congress.

Biden also voted several times, including in 1983, to prohibit federal workers from using health insurance on abortion services, with the only exception being to save the life of the mother.

A devout Roman Catholic, Biden says he personally opposes abortion and has spoken openly about his internal struggles with the issue.

In his 2007 book “Promises to Keep,” Biden describes his beliefs and voting record on abortion as “middle of the road.” He wrote that he doesn’t think he has “a right to impose my view on the rest of society” and committed to protecting Roe v. Wade, the 1973 Supreme Court decision establishing a constitutional right to abortion. In a recent email to supporters, Biden underscored: "I refuse to impose my religious beliefs on other people."

As recently as Tuesday, Biden reaffirmed his support for Roe, telling voters in New Hampshire that it is “the law of the land, a woman has a right to choose.” He added that if the Supreme Court overturned Roe v. Wade while he was president, he would “push” legislation to keep it legal.

Yet his presidential campaign confirmed to NBC News that Biden still supports the Hyde Amendment, a four-decade-old ban on using federal funds for abortion services, except in cases of rape, incest or to save the life of the woman.

Biden’s continued support for Hyde not only sets him apart from the rest of his 2020 Democratic competitors, but it may surprise progressive groups like the American Civil Liberties Union, which promoted a recent tweet by one of its activists appearing to get Biden to commit to ending Hyde during a rope-line exchange in South Carolina. Biden’s campaign told NBC he would be open to repealing Hyde if abortion avenues currently protected under Roe were threatened.

Since 1976, Congress has passed various versions of the Hyde Amendment, which directly affects Medicaid and the low-income families it serves. It wasn’t until 1993, with abortion-rights supporter Bill Clinton newly elected to the White House, that states were required to help pay for abortions for low-income women made pregnant through rape or incest.

With a surge in state laws effectively banning abortion and a new conservative majority on the Supreme Court igniting a political firestorm over the fate of Roe, Biden’s beliefs and voting record puts him at odds with his presidential competitors in an increasingly progressive Democratic Party.

All of the female senators running for the Democratic nomination — Kamala Harris of California, Kirsten Gillibrand of New York, Amy Klobuchar of Minnesota and Elizabeth Warren of Massachusetts — are co-sponsoring legislation to overturn the Hyde Amendment. And no other Democratic presidential candidate has come out in support of keeping the law.

Harris last week supported a plan to block the state abortion bans, arguing that nationwide access is already under assault.

Biden released a video late last month calling the new state laws, many allowing no exceptions for rape and incest, “pernicious” and “wrong.” His campaign also says he would support new federal laws protecting Roe.

Jamal Brown, Biden's press secretary, said the candidate’s evolution on the issue is well documented. Biden, who said he thought Roe was wrongly decided when he arrived in the Senate in 1973, now “firmly believes that Roe v. Wade is the law of the land and should not be overturned,” Brown said. He added that Biden “has fought vigorously to protect a woman's right to choose and against measures criminalizing abortion. As chairman of the Judiciary Committee, he blocked the Supreme Court nomination of Judge Robert Bork and he opposed anti-choice justices Roberts, Alito and Thomas.”

Planned Parenthood criticized Biden’s continued support for the Hyde Amendment.

“The unfair Hyde Amendment makes it so that those who have the least end up having to pay the most to access abortion, and those who are service members or live on reservations are often left with no coverage for abortion care,” Kelly Robinson, the Planned Parenthood Action Fund's executive director, said in a statement to NBC.

“We encourage any candidate who doesn't recognize Hyde's impact to speak to the women it hurts most — particularly women of color and women with low incomes — to learn more about the harmful impacts of this discriminatory policy," Robinson said.

Biden’s Senate record doesn’t just contrast with his current peers.

In that 1981 vote, he was one of just two Democratic senators from the Northeast, the other being George Mitchell of Maine, to vote to end federal funding for abortion for victims of rape and incest. Fellow Catholics Ted Kennedy of Massachusetts and Daniel Patrick Moynihan of New York as well as Democrats from other blue-leaning Northeastern states supported the exceptions. Biden voted in line with conservative Republicans like Jesse Helms of North Carolina and Democrats from red states like Robert Byrd of West Virginia.

Unlike some other neighboring states, Delaware had a Republican voting history in the 1980s. It voted for Ronald Reagan twice, and the state’s governor until 1985, Pete du Pont, and other senator at the time, William Roth, were also Republican. Like Biden, Roth opposed the exceptions.

Biden’s history also puts him at odds with his party’s official platform. During the 2016 campaign, the party’s first female presidential nominee, Hillary Clinton, put an end to the Hyde Amendment in the platform.

A 2016 survey illustrates why the debate over abortion remains so volatile in America — and so uncomfortable for any Democrat looking for a “middle ground.” As the party moves to loosen some abortion laws in order to protect Roe, 58 percent of Americans still remain opposed to allowing Medicaid funds to be used for abortion, the Harvard School of Public Health poll found.

Politics versus personal beliefs

Biden has long spoken openly about his struggle to reconcile his religious and cultural views with his “political responsibility.”

In 2007, he told NBC’s "Meet the Press" that he’s now comfortable with “the decision I’ve come to,” which is that Roe “is as close as we’re going to get as a society” to a position that respects both religious beliefs and that “says there is a sliding scale relating to viability of a fetus.”

The Biden campaign highlighted endorsements from women’s reproductive rights groups including NARAL and Planned Parenthood in 2008 when then-Sen. Barack Obama chose him as his running mate and his 93 percent rating from the National Family Planning & Reproductive Health Association.

But the former vice president’s record of public letters and newspaper interviews suggest he has had strong personal feelings against abortion.

In a 1994 letter to constituents — written during negotiations over health care during the Clinton administration — Biden noted he had “on no fewer than 50 occasions” voted against federal funding for abortions. “Those of us who are opposed to abortions should not be compelled to pay for them,” Biden wrote on April 7, 1994.

In March of 1986, he told the Catholic Diocese Newspaper that “abortion is wrong from the moment of conception” and seemed to offer the National Conference of Catholic Bishops moral support in pushing for limits, noting the “most effective pro-life groups are those who keep trying to push back the frontier.”

“I think medical science is moving the frontier back so that by the year 2000 we’re going to have more and more pressure, and rightfully so in my view, of moving back further and further the circumstances under which an abortions can be had,” Biden told the paper.

And while Biden later became a staunch defender of Roe, in addition to consistently opposing federal funding of abortions, he did vote in 1981 for a failed constitutional amendment allowing states to overturn Roe. At the time, he called it “the single most difficult vote I’ve cast as a U.S. senator.”

When it came up again the following year, Biden voted against the bill.