Nicholas Kristof’s recent New York Times column, “Profiting From a Child’s Illiteracy,” suggests that America must choose between creating opportunity for children with severe disabilities and families living in poverty, or helping them meet basic needs like food, shelter, and medical care through the Supplemental Security Income (S.S.I.) program. Unfortunately, Mr. Kristof misses what’s really at stake.

S.S.I. is a lifeline for over 8 million low-income Americans, including over 1.3 million children with significant disabilities. Benefits are modest, averaging about $600 per month for children in Kentucky, where Mr. Kristof visited, but are invaluable in meeting the often extraordinary costs of raising a child with a disability.

S.S.I. is reserved for low-income children and adults with the most severe disabilities. Despite the misperceptions of some people Mr. Kristof interviewed, low literacy and poor grades on their own do not qualify a child for S.S.I., and doing well in school does not mean a child will lose benefits. Instead, to qualify for S.S.I. a child must have a medically documented impairment that results in “marked and severe functional limitations” of substantial duration. Because the S.S.I. childhood disability standard is so narrow, the majority of children who apply are denied and as documented in recent research by the National Academy of Social Insurance, fewer than 1 in 4 children with disabilities receive benefits.

Childhood S.S.I. trends reflect broader patterns of childhood disability. About two-thirds of child S.S.I. beneficiaries have a primary diagnosis of a mental disorder. This rate has been remarkably stable for 15 years and mirrors World Health Organization researchers’ findings that about 67 percent of youth with disabilities have a mental disorder.

Within the S.S.I. mental disorder category, a shift has occurred. In recent decades the share of children with “mental retardation” (now called intellectual disability) has declined while the share of children with other mental impairments has increased as medical professionals developed more specific diagnoses, such as autism. Intellectual disability, far from being “fuzzy,” has a precise SSI definition of “significantly subaverage general intellectual functioning with deficits in adaptive functioning.” Children in this S.S.I. diagnostic category typically have severe underlying disabilities such as Down syndrome and Fragile X, usually determined only after lengthy medical evaluation and testing.

As documented by Mark Stabile and Sara Allin in a recent article in the journal The Future of Children, families raising child S.S.I. beneficiaries often face enormous, diverse challenges. Many children need ongoing help with activities such as eating, bathing, dressing, toileting, communicating, mobility, and behavior management. Out-of-pocket costs include expensive items such as wheelchairs, ramps, and communication devices as well as lower but persistent costs such as adult diapers for some older children, special foods for medically-prescribed diets, and co-pays for ongoing therapies and doctor visits. Add the costs when a parent must take time off work, stop working, or forgo employment and educational opportunities to help manage medical appointments and around-the-clock personal caregiving. Unsurprisingly, Susan Parish and other researchers at the University of North Carolina at Chapel Hill have documented that families caring for children with disabilities are over twice as likely as other families to experience hardships such as homelessness, food insecurity, and utility shutoff.

The suggestion that S.S.I. keeps families in poverty is like blaming lifeboats for floods: only children in families with extremely low incomes and savings can qualify in the first place. Indeed, children’s S.S.I. enrollment has grown at about the same rate as child poverty. Between 2000 and 2011, a fairly stable 3 to 4 percent of low-income children received S.S.I.

High poverty in economically-depressed states like Kentucky means that more children with severe disabilities in those states meet the S.S.I. income and asset tests. Research also correlates poverty with a higher incidence of childhood disability. Poor families often have inadequate access to nutritious food or prenatal and early childhood care, and greater exposure to environmental hazards such as lead paint and contaminated water.

Most alarming is Mr. Kristof’s recommendation that policymakers take money from S.S.I. and devote it to other early childhood initiatives. Early intervention services – such as speech or behavior therapies, medical care, Head Start, and family education – are vital to ensuring that children with significant disabilities reach their fullest potential. S.S.I. serves as a complement, meeting expenses these important programs don’t cover. Early childhood initiatives don’t pay the rent when a parent is unable to work because a child needs round-the-clock care. Cuts to S.S.I. would have devastating consequences for already vulnerable children.

In today’s heated political climate, with deficit reduction center stage, what’s at stake is the well-being and future opportunities of children with severe disabilities, and the families who care for them in the face of often crushing economic challenges. Congress must preserve S.S.I., not slash this vital benefit when it’s needed most. It’s a matter of life and death.