Instead, Republicans attempted to frame mounting national debt as solely a spending problem, not a tax-revenue problem, even though tax cuts by both parties have added trillions to the debt since the turn of the century.

Republican leaders now appear poised to introduce a new round of tax-cut proposals, which would likely be financed with borrowed money, a move Democrats decried during the floor debate over the debt-ceiling deal.

“Before the ink is dry on this bill, you will be pushing for $3.5 trillion in business tax cuts,” Representative Gwen Moore, Democrat of Wisconsin, said shortly before the final vote on the Fiscal Responsibility Act, as it is called, on Wednesday.

Those comments reflected a lesson Democrats took from 2011, when Washington leaders last made a big show of pretending to care about debt in a bipartisan deal to raise the borrowing limit. That agreement, between President Barack Obama and Speaker John Boehner, limited discretionary spending growth for a decade, helping to drive down budget deficits for years.

Many Democrats now believe those lower deficits gave Republicans the fiscal and political space they needed to pass a tax-cut package in 2017 under President Donald J. Trump that the Congressional Budget Office estimated would add nearly $2 trillion to the national debt. They have come to believe that Republicans would happily do the same again with any future budget deals — putting aside deficit concerns and effectively turning budget savings into new tax breaks.