“They are facing a lot of headwinds” in selling the plan, because Americans will not see it as a boon to the middle class, said Andrew Bates, a spokesman for the liberal opposition research group American Bridge, which is gearing up to oppose the Republican plan. “This plan is vulnerable, based on that landscape.”
As they prepare to release a full tax plan in the coming weeks, though, Republicans are pressing the argument.
“Fixing the business side of our tax code is really all about helping families and workers,” House Speaker Paul D. Ryan, Republican of Wisconsin, said last week. “Cutting the corporate tax rate means more jobs here in the United States. It will foster increased competition, which will directly drive up wages for our workers. Higher wages means bigger paychecks.”
The ability of Republicans to move forward with a tax bill got a boost on Tuesday, as Senator John McCain, Republican of Arizona, said he would support a budget resolution that will clear the path toward legislation. “I support the Senate budget resolution because it provides a path forward on tax reform,” Mr. McCain said in a statement.
The parliamentary language in the resolution would allow Republicans to pass tax cuts that cost as much as $1.5 trillion over the next decade with only 50 votes in the Senate, not the 60 needed to overcome a filibuster. Republican leaders have said that without a budget, there will be no tax cut.
In a speech at the Heritage Foundation in Washington on Tuesday evening, Mr. Trump called on Congress to quickly pass “incredible tax cuts” that he said will allow individuals, big corporations and small businesses to keep more of the money they earn.
Mr. Trump said his tax plan would expand the number of low-income people who pay no taxes, increase the child tax credit, lower rates on big corporations and small businesses, and pave the way for a return of trillions of corporate earnings parked overseas by American companies.
“Our tax plan will ensure that companies stay in America, grow in America and hire in America,” Mr. Trump told employees of the conservative organization. “We will lift our people from welfare to work, from dependence to independence, and from poverty to total, beautiful prosperity.”
The president urged Heritage Foundation employees to help the administration put pressure on Republican lawmakers to support the tax cuts, saying that “you will see things happen like have never happened before. We will have employment. We will have jobs. We will have companies moving back into our country.”
He added: “Let’s give our country the best Christmas present of all: massive tax relief.”
Many economists, including ones who served Democratic presidents, agree that lowering corporate taxes could lead to higher incomes for workers. A few, such as Lawrence B. Lindsey, the former director of President George W. Bush’s National Economic Council, have estimated the Republican plan for corporate cuts could lead to income gains of the magnitude that Mr. Trump’s economists are projecting.
But other economists have criticized the Trump team’s estimates as well above what research supports. That includes Mr. Desai, a professor at Harvard Business School and Harvard Law School, who co-authored a study on corporate taxation that Mr. Trump’s Council of Economic Advisers drew upon for its estimate. The report said that a corporate tax cut would increase average household income by $4,000 per year on the low end to as much as $9,000 at the high end.
Mr. Desai, who wrote the study with Harvard’s C. Fritz Foley and James Hines Jr. of the University of Michigan, said his own estimates of the effect of such a rate cut was closer to $800 a year. “I’m a believer in corporate tax reform, and I’m a believer in corporate tax cuts, and I believe they would go to workers,” he said. “But I don’t believe those numbers add up.”
The chief of staff for the council, D.J. Nordquist, said in an email that the $800 estimate was “far” from the academic consensus on the effects of corporate tax reductions on workers. “It’s gratifying to see Professor Desai agrees with us that there is a need for corporate tax reform and that rate reduction is the best way to help the middle class,” she wrote. “But the CEA did not misinterpret the Desai, Foley, and Hines paper.”
Other economists have attacked the council’s estimates in harsher terms than Mr. Desai. Robert J. Shapiro, the chairman of the consulting firm Sonecon and a former economic adviser to President Bill Clinton, said on Tuesday that there was no evidence in United States history of lower federal corporate tax rates driving surges in investment or wages. The council’s mistake, he said, was “in believing that the corporate tax rate determines the investment rate. That’s just not true.”
Polling suggests middle-class Americans are not clamoring for corporate rate cuts, and that they do not expect the Republican plan to reduce their own taxes. Recent polls by ABC News and the Pew Research Center show a majority of Americans would prefer to raise, not cut, corporate taxes.
A new poll from the online research firm SurveyMonkey, shared with The New York Times, shows that only 17 percent of Americans who identify as “middle class” expect their federal taxes to be lower next year than they are this year. That is less than half the rate for Americans who identify as “upper class.”