Politicians love to talk about family. But maybe not yours.

Of all the interest groups and voting blocs courted in a campaign, the family reigns supreme. Presidential candidates from both parties frame themselves as good for families and, by extension, good for the country. And while targeting families seems like an inclusive strategy, it’s actually very exclusive: Candidates speak mostly to the experience of middle-class, married parents. They rarely talk about the struggles of the 30 percent of parents who are not married or the 18 percent of families with childrenwho are in poverty, trying to enter the middle class.

And for most of the 20th century, the American family was simply not on the political radar; its rise to prominence has been recent. In the 1952 campaign, for example, Dwight Eisenhower and Adlai Stevenson rarely mentioned family or parents. Over the next several decades, the few times Republicans or Democrats mentioned “the family,” it was usually in reference to the plight of poor families, disadvantaged children or family farmers.

It was only when the traditional family structure began to unwind, starting in the 1970s — when divorce rates rose, mothers streamed into the workforce and more people began having kids outside marriage — that the parties began to politicize the family. These dramatic changes complicated the lives of many parents and were viewed as an assault on the American way of life, creating dissatisfied constituencies that both parties have furiously tried to court: parents, especially mothers, stressed out by trying to balance increased work and family responsibilities; and more-traditional voters who became deeply concerned about the decline of the conventional family.