Mr. Mnuchin did not respond to a request for comment.
Republicans argue their plan makes everyone a winner — that lower taxes will unleash an enormous swell of economic growth, raising wages, incomes and tax revenue all around.
The historical record does not offer much support for the claim that slashing taxes for the most affluent creates growth. Yet even assuming the rosiest of forecasts, the top 1 percent, according to the Tax Foundation, would still receive close to a $100,000 tax cut — 32 times as much as a middle-income family.
Mr. Mnuchin has offered his own formula for adhering to the standard he laid down, explaining that "any reductions we have in upper-income taxes would be offset by less deductions."
That would require some otherworldly mathematical magic, however.
Consider the list of proposals that would reduce taxes on the rich:
■ Cut the top income tax rate to 33 percent, from 39.6 percent.
■ Cut taxes on capital gains, 70 percent of which flow to the top 1 percent.
■ Eliminate the estate tax, which applies to a tiny number of people, couples that have estates bigger than $10.8 million.
■ Eliminate the 3.8 percent surtax on high earners' investment income that has been used to subsidize health care for poorer Americans.
■ End the alternative minimum tax, which currently limits deductions for high earners.
■ Lower taxes on cash flow and income that passes from small businesses to their owners, which also primarily benefits wealthier Americans.