It attributed some of the problem to an aging population, as more seniors receive retirement payments from Social Security and health insurance through Medicare. Congressional analysts anticipate that the demand for Social Security may exhaust its trust fund in 2034, threatening seniors’ benefits, while the primary trust fund for Medicare could run out in 2052.

Yet there remains little appetite in Washington for a fight over these social safety net programs. While the Trump administration maintains it does not plan to cut Social Security, Medicare or Medicaid, the president and his allies have attacked the programs in recent weeks as a wellspring of waste, fraud and abuse, and Mr. Musk has derisively referred to Social Security in particular as a “Ponzi scheme” and “the big one to eliminate.”

“If we can eliminate certain forms of waste or improper payments in our budget, that’s a good thing, but it’s simply not sufficient to change the long-run trajectory of the budget,” said Michael A. Peterson, the chief executive of the Peter G. Peterson Foundation, which supports deficit reduction. He said there needed to be new reforms and revenues “in order to put the United States on a more sustainable, fixable path.”

For now, Mr. Trump has pledged to pursue significant cuts to other areas of federal spending, primarily targeting government programs that address climate change, education, health, science and the work force. With the aid of Mr. Musk, the administration has already moved to freeze or cancel billions of dollars in federal aid, while dismissing thousands of federal workers and trying to shutter entire agencies, including the Education Department.

“If they improve the efficiency of the government, that would help on the revenue collection side,” said Phillip Swagel, the director of the C.B.O., during an interview earlier Thursday on CNBC, adding the “volatility can go in the other direction, and change is hard.”