President Trump’s agenda in many ways defies those recommendations. He championed several bills in Congress this year that would have reduced federal spending on health care, though none of them passed the Senate.
And while Mr. Trump’s first budget proposal promised to reduce federal deficits and debt, his administration is pushing a tax plan that independent analysts warn could add trillions to the deficit over the next decade, depending on how Republicans fill in crucial details that party leaders have so far declined to specify.
Perhaps most importantly, the framework tax plan includes several measures that analysts say would amount to windfalls for wealthy Americans, even though Mr. Trump has said the wealthy will not benefit from the plan.
The framework released last month would reduce the top income tax rate on individuals to 35 percent, from 39.6 percent today, while leaving open the possibility of levying a higher top rate on top income earners. It would repeal the estate tax, which currently affects only individuals’ estates valued at more than $5.49 million. And it would reduce taxes on so-called pass-through entities — businesses whose owners currently pay federal income taxes on their profits.
Republican leaders are working to ensure the plan does not raise taxes on the poor or the middle class, but details remain to be seen.
An analysis of the framework proposal by the Tax Policy Center in Washington, which made some assumptions about the unspecified details in the Republican plan, found that the gains from the proposal would be heavily concentrated among the very rich.
Maurice Obstfeld, the International Monetary Fund’s chief economist, said the fund was waiting to see the details of the plan but said it should generate revenue rather than increase the deficit, which would help the United States invest in infrastructure and assist its aging population.
“Increasingly, we’re aware that tax systems have to be cognizant of how they affect inequality. And there’s a need in a number of countries to be especially attuned to the needs of the middle class and those with incomes below the median,” Mr. Obstfeld said.
Other economists were more pointed about the effects of Mr. Trump’s tax proposals.
“Those kinds of regressive taxes lead to the creation over time of increasingly more disparate wealth and income inequality,” said Joseph E. Stiglitz, a professor at Columbia University. “So rather than reducing that kind of regressivity, his proposals, as far as one can say, are going to make things worse.”
Over the past three decades, inequality within countries — including in the United States, China and India — has risen primarily because of the skyrocketing growth of incomes at the top.
Some of this is a consequence of how economies are evolving, said Branko Milanovic, an economist at the City University of New York. New technologies are increasing the returns for the most educated, even as robots replace lower-earning workers. Globalization has allowed businesses to cast around the world for cheaper labor, while the decline of unions has left workers with less bargaining power.
But the trend, at least in part, is also because of governments that have redistributed less wealth to poorer people through taxes and spending, the monetary fund suggested.
In the report published Wednesday morning, the fund detailed how governments around the world have shifted away from policies that redistribute wealth from the rich to the poor, and how that has worsened inequality.
Progressivity — the degree to which the average tax rate rises with a person’s income — has fallen sharply in recent decades. Among the advanced economies of the Organization for Economic Cooperation and Development, for example, the average top income tax rate has plummeted to just 35 percent, in 2015, from 62 percent, in 1981.
The monetary fund argued that many countries, like the United States, have room to raise tax rates on the wealthiest without impeding growth.
Many economists believe some inequality can actually be good for the economy by encouraging people to strive and innovate. And the fund emphasized that redistribution should not risk undermining growth, which is the most important factor for helping to narrow gaps between the haves and have-nots.
But research suggests many countries are not near that point. In fact, inequality that is too high can harm growth — if, for example, people from less elite backgrounds are barred from contributing to the economy.
In a speech last month , Lael Brainard , a governor at the Federal Reserve, said that historically high levels of income and wealth inequality in the United States may be weighing on consumer spending, which fuels the majority of economic activity. That is because the wealthiest households are most likely to save a larger proportion of any additional income they earn, rather than spend it, Ms. Brainard said.
In its report, the monetary fund calculated that policies that redistribute wealth from the highest earners to the lowest reduce inequality in advanced economies by roughly one-third. Three-quarters of that reduction is achieved by transfers, while one-quarter is because of taxes, it said.
Even as wealthy countries have slashed the rate for the highest earners, many have also increased the thresholds for the kind of tax exemptions that help the poor. The cumulative effect has been to shift the tax burden from very low and very high incomes toward the middle class, the fund said.
Along with making taxes more progressive, the fund urged countries to fairly tax capital income, like business profits and interest earned on investment. It also recommended tightening deductions that benefit the wealthy, like that on home mortgages, and eliminating opportunities for tax evasion.
Even so, the monetary fund’s projections show they may not put much stock in the Trump administration’s plans. Compared with its previous projections, the fund is now assuming a tighter fiscal stance — that is, fewer tax cuts and less government spending.
