All of which may complicate Casey’s reelection battle, forcing him to defend his voting record in heavily Catholic Pennsylvania as he attempts to hold off a challenge from GOP Rep. Lou Barletta.

Barletta seized on the issue immediately after Justice Anthony Kennedy announced his retirement last week. “I’m 100 percent pro-life,” Barletta said. “According to his voting record, he’s voted only 20 percent for life in the 115th Congress.”

Casey said he opposes the Roe decision legalizing abortion but is “highly unlikely” to back anyone on Trump’s already public list of nominees.

The two-term Democrat insists that Pennsylvanians know the depth of his opposition to abortion — one that is closely linked to his father’s reputation as perhaps the nation’s best-known anti-abortion Democrat — and that Washington advocacy organizations and their scorecards don’t say much about moderates like him.

“I think it’s clear to most people that the description of pro-life Democrat is accurate. I’ve been very consistent,” Casey told POLITICO in an interview. “What it means is I try to support policies that help women and children both before and after birth. Part of that is making sure you are honest about differences but also at the same time trying to focus on ways to reduce both the number of abortions and the number of unwanted pregnancies, and I think my record reflects that.”

Casey’s voting record in Congress aligns significantly with abortion rights groups such as Planned Parenthood and NARAL. He has voted along with Planned Parenthood 75 percent of the time since 2011. And he voted with NARAL Pro-Choice America 100 percent of the time in 2016and 2017, although his 2018 rating is sure to be lower.

Earlier this year, the senator backed a GOP measure to ban abortion at 20 weeks of pregnancy, earlier than current law allows, which will bolster Casey’s anti-abortion record. But for much of the anti-abortion movement, it’s not enough.

The 20-week ban “should have been an easy vote for all members of Congress,” said Carol Tobias, president of National Right to Life Committee, which in mid-June endorsed Barletta.

Like many conservative organizations, National Right to Life puts a huge emphasis on the impact the courts can have on the future of abortion policy.

“The telling vote was against Neil Gorsuch to the Supreme Court,” Tobias said of Casey. “That was critical.”

Scorecards are an imperfect calculation of a lawmaker’s position. Each organization calculates them differently, and groups on both sides of the abortion debate have swept in tangentially related issues, such as Supreme Court nominees, contraception, Obamacare repeal, free speech and even the Senate filibuster rules.

Casey’s campaign broke down the votes on each of the three scorecards for POLITICO and said that under their calculation, 15 pieces of legislation in Casey’s career dealt directly with abortion. Casey cast the anti-abortion vote on 13 of those measures, which covered issues such as the 20-week abortion ban, funding for the United Nations Population Fund, prohibiting abortion in the Indian health program and restricting minors’ access to abortion.

Two votes were considered in support of abortion rights, including opposition to prohibiting access to private health plans that cover abortion and prohibiting medication abortion.

“Some groups have an overwhelming preference for one party. I think that’s pretty clear. There are Republican groups and Democratic groups. No matter what one side or another does or what your voting record is, they’re going to apply a label to you,” Casey said, alluding to the fact that anti-abortion groups increasingly align with Republicans. “In the end, groups down here are not going to be an arbiter of what happens in Pennsylvania. People in our state, they know me pretty well by now. They’ll take in all that information and make their own decision.”

It’s true Casey walks a different path on an issue in which the vast majority of lawmakers Velcro themselves to their party’s ideological position.

Like conservative anti-abortion groups, he opposes the Roe decision and opposes the taxpayer funding of the procedure. But like progressive abortion rights organizations, he supports Obamacare, access to contraception through programs such as Title X and funding for Planned Parenthood.

All three of those issues have become significantly more contentious in recent years — and drive up Casey’s scorecard among abortion rights groups. The debate over Obamacare — including whether insurance policies would cover abortion — dramatically pulled apart the parties on abortion, a rift that is still visible. A 2015 series of sting videos alleging that Planned Parenthood sold fetal body parts made funding for the organization extremely controversial.

But Casey argues that supporting Obamacare and backing access to contraception and Planned Parenthood funding are anti-abortion positions.

“The evidence is pretty strong: if you have access to family planning and birth control, the abortion rate is going to go down. There are fewer unwanted pregnancies and fewer occasions where a woman is confronted with that decision if she has access to family planning and birth control,” Casey said. “That’s why I support Planned Parenthood; that’s why I support Title X.”

One anti-abortion group continues to view Casey as an ally. “He is absolutely a pro-life Democrat,” said Democrats for Life executive director Kristen Day. “Planned Parenthood funding — that’s the one area of disagreement. But he’s still a pro-life Democrat.”

Casey has put an emphasis on pregnancy support programs, an issue that he says should get more support from all lawmakers, no matter their position on abortion. He’s introduced legislation to require employers to make reasonable accommodations for pregnant women in the workplace, and he’s backed funding for maternal health programs.

“We can debate this issue all day, or we can focus on areas of common ground — it’s as simple as three words: help pregnant women,” Casey said. “If both sides are doing that, not only would the number of unwanted pregnancies go down, but you’re more likely to have women with healthy pregnancies.”

Barletta isn’t likely to debate the nuances in the upcoming campaign, instead arguing Casey has lost all credibility as an opponent of abortion.

“Bob Casey Jr., when he was elected, was pro-life in his first term,” Barletta said. “But he has moved so far left since then he has no record voting for life any longer. There is a misconception by some that he is still a moderate pro-life Democrat, and his record mirrors Elizabeth Warren’s.”

Unlike the few other anti-abortion Democrats on Capitol Hill, Casey’s credentials have to compete with a family legacy. His father, former Pennsylvania Gov. Bob Casey, was perhaps the nation’s best-known “pro-life Democrat.”

In 1991, Casey Sr. asked the Supreme Court to overturn Roe in Planned Parenthood v. Casey, a now-famous ruling that enshrined the Roe decision but allowed states to enact hurdles to access. And he was banned from making an anti-abortion speech at the 1992 Democratic National Convention.

Barletta and anti-abortion groups are quick to make the comparison — National Right to Life, in announcing its endorsement of Barletta, delivered a stinging personal rebuke to the senator by comparing him to Casey Sr.

“Bob Casey is not his father,” Tobias said in the statement.

Marilyn Musgrave, vice president of government affairs at the Susan B. Anthony List, said Casey Jr. has “squandered” his father’s legacy.

“His father paid a price for being pro-life,” Musgrave said. “Sen. Casey is trying to have it both ways now.”

Casey declined to compare his record with his father’s but hinted that it’s an apples-to-oranges comparison.

“It’s natural when you have two people in the same family in public office you’re going to have those comparisons, and I have them on a range of issues,” he said. “But those comparisons are always extraordinarily difficult, usually unfair to both sides and impossible to do accurately because you have different people in different positions in public office at different times.”