Futile and destructive as it was, that episode at least stemmed from a struggle over actual fiscal policy. Specifically, Republicans in the mid-1990s refused to approve funding unless then-President Bill Clinton agreed to their terms for a seven-year plan to balance the federal budget — before the GOP capitulated and accepted Mr. Clinton’s approach, because of the political costs of their holdout. Today’s clash is a purely political and symbolic one over how much more to spend, if anything, on Mr. Trump’s border wall.

A new report from the Congressional Budget Office is enough to make one nostalgic for the days when at least some people cared enough about fiscal profligacy to fight about it. Instead, all of Washington shrugged at the CBO’s chastening message: The United States is running up an unprecedented peacetime debt and, without budget cuts or tax increases, paying interest on that debt will increasingly compete for resources with other vital public purposes, such as defense, education, scientific research and fighting recessions.

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Especially striking in the report was its estimate of just how large a fiscal adjustment the United States would need to attain quite modest ­debt-reduction objectives. At present, the national debt is equal to 78 percent of GDP, the highest level since 1950 and almost twice the postwar average of 41 percent. Simply to arrive at the year 2048 without increasing debt beyond its current level would require noninterest spending cuts and tax increases totaling 1.9 percent of GDP, as compared with current projections, each year for the next three decades. (That would have worked out to $400 billion in fiscal 2019.) To get back to the postwar average debt level of 41 percent of GDP by 2048 would take 3 percent of GDP in savings each year.

Mr. Trump and his fellow Republicans are responsible for much of the problem, having slashed taxes, mostly for the well-to-do and business, without even trying to offset that with budgetary discipline elsewhere. Many Democrats are eager now to take their turn. For all its technocratic framing, the CBO report simply expresses common sense: The longer we put off necessary fiscal adjustments, the more expensive and politically difficult they will be when the time to make them comes — as it inevitably will.