The debate over whether the United States is risking its economic future by running up ever-larger government debt has flared and sputtered for decades.
President Trump’s dogged pursuit of an expensive set of tax cuts has reignited that clash, but with new urgency.
The federal government’s publicly held debt is already at its highest level since World War II, measuring at about 100 percent of the size of the economy. It is set to grow at a rate that most economists believe would be unsustainable.
The question of whether the nation can afford to remain on its current path is complicating the White House’s efforts to nail down support for Mr. Trump’s domestic policy bill, which includes the tax cuts. The proposal is expected to add $2.4 trillion to the debt over the next decade, according to an estimate from the nonpartisan Congressional Budget Office.
But that price tag does not include an additional $551 billion in costs that the United States would have to incur to sustain that level of borrowing, congressional scorekeepers predicted on Thursday, as they warned that debt held by the public would total nearly 124 percent of the nation’s gross domestic product by 2034 if the bill were to become law.
The figures have exposed disagreements among Republicans that have been papered over in recent years, and have contributed to growing unease on Wall Street over the extent to which the White House may exacerbate the sort of borrowing Mr. Trump has promised to reduce.