The federal government could soon pay more in interest on its debt than it spends on the military, Medicaid or children’s programs. The run-up in borrowing costs is a one-two punch brought on by the need to finance a fast-growing budget deficit, worsened by tax cuts and steadily rising interest rates that will make the debt more expensive.

The amount of corporate taxes collected by the federal government has plunged to historically low levels in the  first six months of the year, pushing up the federal budget deficit much faster than economists had predicted. The reason is President Trump’s tax cuts. The law introduced a standard corporate rate of 21 percent, down from a high of 35 percent, and  allowed companies to immediately deduct many new investments.

As a candidate, Mr. Trump declared that he understood America’s complex tax laws “better than anyone who has ever run for president” and that he alone could fix them. But it is becoming increasingly unlikely that there will be a simpler system, or even lower tax rates, this time next year. The Trump administration’s tax plan, promised in February, has yet to materialize; a House Republican plan has bogged down, taking as much fire from conservatives as liberals; and on Monday, Treasury Secretary Steven Mnuchin told The Financial Times that the administration’s goal of getting a tax plan signed by August was “not realistic at this point.”