Several members of Congress, particularly Democrats facing difficult re-election races, have clamored in recent days for Mr. Biden to invoke the law to ease the formula shortage. It was not clear how quickly the impact would be felt.
A White House official, speaking on the condition of anonymity and without authorization to comment on the plan, said it could take time for companies to make use of the Defense Department’s offer to ship formula. But the official added that Mr. Biden was determined to do anything he could to shave even a few days off the manufacture and distribution of formula.
The White House offered details on the effort as it confronted aggressive questioning by Congress. In recent days, lawmakers have announced plans to haul administration and industry officials to Capitol Hill for testimony, demanded answers from Mr. Biden’s team on how the shortage was allowed to develop, and launched investigations into the crisis and Abbott Nutrition, the company that recalled several of its formula products after at least two infants died.
On Wednesday evening, the House was expected to approve bipartisan legislation that would grant the federal government emergency authority to expand the types of formula that can be purchased with benefits from the Special Supplemental Nutrition Program for Women, Infants and Children, known as WIC. About half the formula sold in the United States is purchased with WIC benefits, and the legislation aims to ensure that those benefits can be used to buy whatever formula is available.
But the proposal to issue emergency money for the F.D.A. was likely to face a more difficult road amid opposition from Republicans, who said it was a blank check for an agency that had failed to prevent a major crisis.
In a notice sent to rank-and-file lawmakers, Republican leaders charged that Democrats had abandoned bipartisan talks and instead put forward legislation “with no plan to actually fix the problem, all while failing to hold the F.D.A. accountable.”
The WIC measure, by contrast, was expected to draw broad support.
“I know what it means to not be able to stretch out milk for the entire month,” Representative Jahana Hayes, Democrat of Connecticut and a sponsor of the bill, said this week. Ms. Hayes, who said she had used WIC benefits to purchase formula added, “with everything going on right now, the last thing a family should have to worry about is feeding their children.”