But there is a substantive generational argument to be made here. Although public opinion on abortion has stayed relatively steady for four decades, support for legalizing the procedure under any circumstance spiked in the early 1990s, when today’s fortysomethings were coming of age. Their younger peers haven’t had a similar shift in attitudes, though. Even though Millennials feel more open to things like pre-marital sex and same-sex marriage than their older siblings and parents and grandparents, they still feel conflicted about abortion. According to a 2015 report by the Public Religion Research Institute, 55 percent of people born between 1980 and 2000 believe abortion should be legal in most or all cases, while 42 percent believe it should be illegal in most or all cases—roughly the same proportion as the rest of the country. Although today’s twenty- and thirty-somethings grew up in a time when abortion was more common than ever before, they’re not choosing to have abortions themselves.

And as with the rest of America, Millennials’ beliefs are strongly shaped by religious faith. Eighty percent of young, white evangelical Protestants and half of young Catholics said abortion should be mostly or completely illegal, while nearly 80 percent of religiously unaffiliated Millennials said the opposite. In many ways, this statistic is the most important for understanding attitudes toward abortion in the United States. Many people see it as a moral issue, because it necessarily involves defining what “life” means; on this kind of topic, a lot of people look to their faith.

Religion largely determines the politics of abortion, too. White evangelical Christians are much more likely than any other group to say they’d vote against a political candidate because he or she supported abortion. They are also a core voting bloc for the GOP. “There are a lot of evangelicals … who might, if we had a different sort of political climate in this country, be voting different ways,” Russell Moore, the head of the political-advocacy arm of the Southern Baptist Convention, told me earlier this year. “But when you have only one pro-life party, and when you have a Democratic Party that right now is completely committed to abortion … people are voting on issues that are most important to them.”

Meanwhile, in the lives of regular people, the choice to have an abortion or not is complicated, and intensely personal. A large share of Americans don’t feel comfortable describing themselves as either pro-life or pro-choice, or feel that both labels might describe them in some way. This ambiguity is evident in the emerging abortion trends: A growing percentage of women describe themselves as pro-choice, but they still form only a slight majority. Access to abortion is becoming more difficult, but that doesn’t necessarily explain why women aren’t getting the procedure. Birth control is more affordable, but women aren’t necessarily using it. Attitudes toward sex are changing broadly, but not attitudes toward unintended pregnancy. It’s an important reminder in a year of big changes on social issues like same-sex marriage: Politicians may use the same recycled rhetoric in election after election, and Americans’ attitudes on abortion may stay pretty much the same. But in their lived-out lives, Americans are moving away from embracing abortion, not toward it.

* This article originally stated that the Planned Parenthood v. Casey decision was handed down in 2000, rather than 1992. We regret the error.

** This article has been updated to clarify that the CDC estimate reflects the percentage of unintended births, not pregnancies, as of 2010.

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