Read: Divorce and the family in America

In some ways, the fact that Americans could soon see one of these family structures in the White House is a return to form. The early years of the United States saw more diverse first families; specifically, Perry says, more presidents had blended families or lacked wives or children, but that usually had more to do with high mortality rates from illness than with divorce. James Madison had no children of his own, but his wife, Dolley, a widow when they married, had one son. Of course, at that time, stepfamilies were so common that they were barely distinguished at all from other families, says Catherine Allgor, the president of the Massachusetts Historical Society. “A man had dominion over all his children, whether they were his or not,” she says. (Other presidents are today known to have had children with multiple partners, though it wasn’t common knowledge at the time. Warren G. Harding, for example, was found in 2015 to have fathered a child with a woman who was not his wife. Thomas Jefferson, a widower when he took office, is now widely believed to have fathered multiple children with Sally Hemings, his slave.)

Allgor, whose research specializes in the lives of the first ladies, also notes that in early American history, it wasn’t so much the structure of a candidate’s family that mattered to voters so much as whether a candidate and his wife seemed like an effective governing team. First ladies, she says, often hosted the social gatherings where the unofficial political dealings of Washington took place at the time—so a worldly or charismatic first lady, such as Louisa Adams or Dolley Madison, could be a boon to her husband’s campaign.

Despite the long-held tradition of the president being a husband and a father, the American people have elected bachelor presidents—such as James Buchanan in 1857 and Grover Cleveland in 1885. (Cleveland famously got married while in office, becoming the only president to ever marry at the White House. He was also accused of fathering a child before he married, and not with the woman who eventually became his wife.) Still, Allgor notes, Buchanan appointed his niece, Harriet Lane, to the role of first lady during his presidency. “A male politician needed a woman by his side, and it didn’t necessarily have to be one he was married to,” she says. “In the 19th century, people recognized this—that for politics to happen, you needed these two spheres, the official and the unofficial.”

By the late 20th century, when advances in medicine, a prospering postwar economy, and a Baby Boom resulted in a higher rate of intact nuclear families, nontraditional family structures had become controversial enough that having one could nudge a presidential candidate out of contention. Perry, who has written three biographies of members of the Kennedy family, notes that John F. Kennedy’s father urged him to marry in his early 30s to preempt any unwanted questions that might arise about the sexual orientation of an unmarried candidate for political office. Adlai Stevenson was divorced, Perry points out, when he ran for president in 1952 and 1956; when his first wife died in 1972, her obituary said their divorce had been “considered a liability” to his campaign. And when Nelson Rockefeller, then the governor of New York, briefly left the presidential-campaign trail to be with his new wife for the birth of their first child in 1964, he drew attention to the fact that he and his wife had both left their previous spouses, and he narrowly lost the California Republican primary to Barry Goldwater. Though that isn’t necessarily why he lost, Perry thinks it didn’t help. “The people thought that was just so horrible,” she says.