The burden of care has not become a political concern with the urgency of health care policy; it is mostly absent from proposals by candidates for the Democratic presidential nomination. But it is seeping into the conversation. Senator Bernie Sanders’s Medicare for All proposal includes a benefit for long-term care. Senator Elizabeth Warren supports universal child care, which she has proposed to finance with a wealth tax.

Ms. Poo argues that it is only a matter of time before care becomes a political priority. “There is no feasible way in this economy that people can manage care without more institutional support,” she said.

And the economic benefit would be substantial. A 2015 study by the Labor Department estimated that if prime-aged American women worked as much in the formal work force as their counterparts in Canada or Germany — which have more generous policies to subsidize care for the young, the sick and the old — 5.5 million more women would have been in the labor force in 2014, increasing gross domestic product by 3.5 percent.

In 2004, California became the first state with a paid family-leave benefit. It offered six weeks of partly paid leave for workers with a newborn, a sick relative or other caring needs. One study concluded that the benefit significantly increased the share of mothers who returned to work one year after giving birth. Other studies have also found some evidence that paid leave increases the labor participation of mothers, particularly those in less-skilled jobs. Some researchers have found that paid leave can raise mothers’ wages over the long term, by preventing them from having to interrupt their careers to care for young children.

Half of Americans who reach 65 will need long-term care, typically for two years, according to government projections. The bill will be $266,000. A little more than half will come out of the pocket of the person receiving the care and the family. In the typical case, these people will spend their resources until they become indigent enough to qualify for Medicaid. Once they are poor, they can be covered: Medicaid pays over a third of the country’s long-term-care costs.

In June, the National Academy of Social Insurance published a report exploring ways in which care for the young, the old and the sick could be added to America’s social insurance package.

One option the academy considered would cover child-care expenses exceeding 7 percent of household income. It would cover part of the salary of people who took leave to care for a relative. And it would pay for about $36,500 worth of long-term care over a lifetime. This would not cover the entire tab faced by families, but it would go a long way toward easing their financial strain.