Rand Paul, at the Values Voter Summit, in September. Photograph by Mark Peterson/Redux

In my recent Profile of Senator Rand Paul, Dr. John Downing, the Senator’s friend and former medical partner, expressed his worries about Paul's sponsorship of the Life at Conception Act, also known as the personhood law. The bill would ban abortion and grant the unborn all the legal protections of the Fourteenth Amendment, beginning at “the moment of fertilization.” To Downing, who is an ardent Paul supporter, this seemed like political madness. Downing said that he believed Paul’s personhood law would make some common forms of birth control illegal, and thus doom Paul’s Presidential hopes. “He’s going to lose half or more of women immediately once they find out what that would do to birth control,” Downing told me.

Downing’s concern was that common forms of emergency contraception—Plan B, which is sold over the counter, Ella, and others—as well as intrauterine devices (I.U.D.s), a common form of birth control, could be banned if the Life at Conception Act became law.* Echoing the views of many opponents of personhood laws, Downing argued that these birth-control methods prevented a fertilized egg from implanting in a woman’s uterus and so, under Paul’s proposal, could instantly be reclassified as weapons of murder.

Whether these birth-control methods actually work that way is another question. The scientific understanding of emergency contraception has changed in the last decade. Whereas a string of older studies suggested that Plan B and similar drugs prevent a fertilized egg—a human, according to Paul’s bill—from implanting, the latest research strongly indicates that these drugs “prevent pregnancy primarily by delaying or inhibiting ovulation and inhibiting fertilization.” But the scientific answer is not an absolute one. As a comprehensive review of the academic literature, published in August, explains, “it is not scientifically possible to definitively rule out that a method may inhibit implantation of a fertilized egg.” Since doctors, in any event, define the start of a pregnancy as when the egg is implanted in a womb, the small chance that emergency contraception may sometimes work by inhibiting implantation isn’t very meaningful—either way, it prevents, rather than ends, a pregnancy.

For pro-life activists, though, this uncertainty is enormously consequential. If you believe a fertilized egg is no different from a human being, then the risk—even if it’s one in a thousand—that a drug could kill that human is intolerable. (In Burwell v. Hobby Lobby, the Supreme Court case in which a craft-store chain successfully sought an exemption from the Affordable Care Act, a central issue was coverage of birth control that the company’s owners considered “abortifacients,” because of their possible effect on fertilized eggs.)

Paul is not a casual defender of personhood. In 2012, he held up a crucial flood-insurance bill in the Senate in order to try to force a vote on a personhood amendment. Aside from his filibuster against John O. Brennan’s nomination to be the director of the C.I.A., Paul’s effort to get attention for this amendment was one of the most dramatic moments of his Senate career.

So it was shocking, last week, when Paul was asked about Plan B during an event in South Carolina, and he nonchalantly declared that he had no problem with women using the so-called morning-after pill. “Plan B is taking two birth control pills in the morning and two in the evening, and I am not opposed to that,” he said.

Predictably, his answer caught the attention of pro-life activists. Just a few days before his stop in South Carolina, Paul had given a speech at the Value Voters Summit, an annual event for social conservatives co-sponsored by the Family Research Council. Paul said that America is in “a spiritual crisis” and promised that he “will continue to stand up in defense of life as long I’m privileged to be in office.”

After Paul’s comments in South Carolina, Tony Perkins, the head of the Family Research Council, posted a pair of tweets criticizing Paul:

https://twitter.com/tperkins/status/517747201821650944

https://twitter.com/tperkins/status/517748483487727616

The response from Paul’s camp was to anonymously attack Perkins and insist that Paul’s position was actually more enlightened, because Plan B works by preventing ovulation rather than by killing a fertilized egg.

Paul, having spent the last few years convincing pro-life activists that he firmly believes that the state should protect fertilized eggs the same way it protects all Americans, now simply shrugs at pro-life concerns over emergency contraception.

Perkins’s position is extreme, but he’s being straightforward about what the ramifications of a personhood law could be for American jurisprudence and family planning. Once the government is in the business of protecting fertilized eggs, which is what Paul says that he wants and is fighting for, all emergency contraception would face new scrutiny—and it’s not possible to predict what drugs or devices would survive the new legal regime. (The use of emergency I.U.D.s, which do prevent implantation of fertilized eggs, would surely not survive.)

“I think we damn well better stay out of the way of women and birth control,” Downing told me. “The Democrats are going to kill the Republicans. There's no way that Republicans can win no matter what they say about it, and they just better shut up. That is a woman's issue and men don't have any business telling women what to do with their bodies."

Some Republicans have heeded that advice, if not consistently. Colorado’s Republican Senate candidate, Rep. Cory Gardner, recently dropped his support for a state-level personhood initiative that’s on his state's ballot this year. “The past four years as I've learned more about it, I've come to the conclusion it can ban common forms of contraception,” Gardner told the Associated Press, in March. (Inexplicably, Gardner continues to support a federal version of the law.)

As with so many other issues—the Middle East, civil rights—Paul has placed himself in a political vise on the question of when life begins. His views on personhood will be savaged by Democrats if he runs for President; and his casual endorsement of Plan B has antagonized leading social conservatives who were already highly skeptical of his pro-life bona fides.

When we talked over the summer, Downing said that he told Paul privately that his best option was to renounce his support for the Life at Conception Act. “So far I haven't gotten anywhere,” Downing told me. “I'm not going to give up yet.”

*Correction: This post originally suggested that Ella is also sold over the counter.