WASHINGTON — Republican lawmakers have misleadingly suggested that the Biden administration is sending baby formula to undocumented immigrants at the expense of American families amid a national shortage.

Around the country, more than 40 percent of formulas are out of stock, caused by supply chain issues and the closure of a major manufacturing plant in February. The limited availability has left parents desperate and scrambling for a solution. The Biden administration announced modest steps on Thursday to address the crisis, and Speaker Nancy Pelosi said on Friday that the House would take action on the issue next week.

The shortage has become fodder for political attacks from Republicans, who have fused the issue with criticisms of the administration’s immigration policies. Democrats have countered that those opposed to providing migrant infants with formula belong to a “pro starvation caucus,” as one lawmaker put it.

But it is inaccurate to suggest that President Biden is choosing to prioritize the needs of immigrant children over those of American children. Providing food — like formula — and water to migrant children detained at the border is required by a lawsuit settlement, and the Trump administration also adhered to that requirement. And it is unlikely that the amount of formula in stock at detention facilities would meaningfully ease the shortage.

Here’s a fact check.

What Was Said

This is misleading. The government must provide food, including baby formula, and water to migrant children detained at the border as part of a settlement of a class-action lawsuit that was initially brought against the Reagan administration and settled under the Clinton administration in 1997.

The Flores settlement, as it is known, laid out the appropriate treatment of children detained by immigration officials, including holding them in “safe and sanitary” facilities and providing “drinking water and food as appropriate.”

Under the settlement, the government also agreed to quickly release children from detention. To get around Flores and detain adults who were traveling with children, the Trump administration separated families at the border. When that policy incited immense backlash, the administration produced regulations to replace Flores, but a federal judge ultimately rejected that effort.

Despite the Trump administration’s antipathy to the settlement, it nonetheless abided by Flores’s food and water requirements. Inspector general reports in 2018, 2019 and 2020 found that all Border Patrol facilities that investigators visited had baby formula available. A news release from Customs and Border Protection in 2019 also noted that facilities provided formula.

Congress itself has explicitly cited infant formula in funding legislation for Customs and Border Protection. For example, lawmakers gave the agency $40.2 million in 2019 for “commodities such as food, infant formula and diapers.”

Like most government agencies, Customs and Border Protection purchases supplies in bulk, typically months or years in advance. For example, the agency awarded a multimillion-dollar contract to a food distributor in 2015 for five years’ worth of meals for detained migrant children in the Rio Grande Valley sector.

Customs and Border Protection did not respond to questions about its procurement process for formula. But the agency said in a statement that “ensuring migrants, including children and infants, in our custody have their basic needs met is in line with this administration’s commitment to ensuring safe, orderly and humane processes at our border.” The agency, the statement said, “complies with all applicable regulations for the purchase of products used in C.B.P. facilities.”

Steven L. Schooner, a professor of government procurement law at George Washington University, was skeptical that the agency’s purchases had any effect on the current supply of baby formula.

“I’m extremely confident that any volume of formula that D.H.S./C.B.P. buys is statistically the equivalent of zero in terms of market share,” he wrote in an email, referring to the agency and the Department of Homeland Security. “Indeed, I’d be stunned if the government bought any significant volume.”

There were 3.6 million births in the United States in 2020, the most recent year with data available. The number of infants detained with their families at the border is far, far smaller. Immigration authorities apprehended just under 38,000 people traveling with a family member in March. Typically, families are detained for no longer than three days, meaning the amount of formula consumed by infants while in detention would be insignificant.

“If someone believes we should starve immigrant babies, then D.H.S./C.B.P.’s supply and supply in transit could be redirected,” Mr. Schooner added.