[Update: On Friday, Susan G. Komen for the Cure announced that it was reversing its decision to break with Planned Parenthood.]

In 1731, Benjamin Franklin’s nineteen-year-old sister, Jane, wrote to her brother that their sister Mary, a mother of three, was dying of breast cancer. Franklin was in Philadelphia; his sisters were in Boston. “I know a cancer in the breast is often thought incurable,” Franklin wrote Jane, “yet we have here in town a kind of shell made of some wood, cut at a proper time, by some man of great skill (as they say,) which has done wonders in that disease among us, being worn for some time on the breast.” Mary died later that year. There was no cure. There is still no cure.

On Tuesday, Susan G. Komen for the Cure, the breast-cancer fund-raiser and sponsor of an annual pink-ribbon Race for the Cure, announced that it would no longer support Planned Parenthood. In 2011, Planned Parenthood received six hundred and eighty thousand dollars from Komen to administer breast-cancer screenings at its clinics.

Komen has been pressured to cut ties with Planned Parenthood for years. This week, it named as the catalyst for its action a congressional investigation into Planned Parenthood launched in September by Cliff Stearns, a Florida Republican. But Stearns’s inquiry, as I reported in the magazine in November, is only one feature of a much broader effort to defund Planned Parenthood. A year ago, that campaign nearly led to a shutdown of the federal government.

The people who have urged Komen to stop supporting Planned Parenthood aren’t opposed to breast-cancer screenings; they’re opposed to other services Planned Parenthood provides, which include contraception and abortion. But a campaign to sever the ties between a foundation that’s raising money to find a cure for breast cancer and a health-care provider that advocates for reproductive rights exposes more than a division over contraception and abortion. It exposes a gruesome truth about politics in this country.

In American politics, women’s bodies are not bodies, but parts. People like to talk about some parts more than others. Embryos and fetuses are the most charged subject in American political discourse. Saying the word “cervix” was the beginning of Rick Perry’s end. In politics, breasts are easier to talk about. I first understood this a few years ago, when I was offered, at an otherwise very ordinary restaurant, a cupcake frosted to look like a breast, with a nipple made of piped pink icing. It was called a “breast-cancer cupcake,” and proceeds went to the Race for the Cure.

Dividing women’s bodies into parts, politically, has only adversely affected women’s health. Planned Parenthood started offering cancer screenings in the early nineteen-sixties. At the time, the organization’s medical director, Mary Steichen Calderone, tried to convince the American Cancer Society to help pay for Pap smears, which can catch cervical cancer early, for poor women who came to Planned Parenthood clinics for contraception. The Cancer Society refused, not wanting to be affiliated with an organization that provided birth control at a time when, in many parts of the country, it was not only controversial—as it remains today—but also illegal. (It was only in 1965 that the Supreme Court ruled, in Griswold v. Connecticut, that contraception was protected under a Constitutional right to privacy.) “It was such a pity,” Calderone later said in an interview, “because here were these women going to be seen regularly, once a year or once every two years. They would have been ideal to give Pap smears to.”

The women’s-health movement, which began in the nineteen-seventies, tried to explain that women’s bodies are not parts, but bodies, and that health care for women must, at a minimum, meet the standards of health care for men. This week’s dissolution of a bond between the nation’s largest funder of breast-cancer research and one of the largest providers of women’s health services suggests just how dismally that effort has failed.

By now, this is, obscenely, a story about partisan divisions, as if some parts of women’s bodies are Democratic and other parts are Republican. The current president of Planned Parenthood, Cecile Richards, a former deputy chief of staff for Nancy Pelosi, is the daughter of the former Texas governor Ann Richards, a prominent Democrat. Susan G. Komen for the Cure was founded in 1982 by Nancy Goodman Brinker, a Texas Republican who went on to serve in the Bush Administration. Karen Handel, Komen’s senior vice-president for public policy, is a Republican who ran for governor of Georgia in 2010. On Thursday, twenty-two Democratic Senators sent Komen a letter asking the group to reverse its decision, Planned Parenthood reported receiving a flood of donations, and New York mayor Michael Bloomberg pledged to match those donations with up to a quarter of a million dollars of his own money.

Brinker has published a number of books, including “Promise Me: How a Sister’s Love Launched the Global Movement to End Breast Cancer.” She named the foundation after her sister Susan G. Komen, who died of breast cancer at the age of thirty-six.

Two and a half centuries ago, Benjamin Franklin’s sister Mary was thirty-seven, nearly the same age as Susan Komen, when she died of the same disease. When Franklin’s sister Jane wrote to her brother in 1731, she didn’t only tell him about Mary. She also wrote that, although her first child had died before reaching his first birthday, she had given birth again, and her second baby, thank God, was thriving. But she had more “melancholy news”: another sister, Sarah, had died. She was thirty-two, and likely pregnant. She left behind five children, the oldest only eight, the youngest eighteen months. “She was a good woman,” Franklin wrote back. He named his only daughter after her.

Jane went on to have twelve children. She named two of her daughters after her sisters. Her daughter Mary died at nineteen. Her daughter Sarah died at twenty-seven. “She was always appeared to me of a sweet and amiable temper,” Franklin wrote Jane. She left behind four children under the age of seven, including daughters also named Sarah and Mary. For the unending pregnancies and difficult deliveries that felled young women, he had no cure. There was no cure. Not then.

Illustration by Matthew Hollister.