Democrats predictably felt differently.

“Each of these proposals would result in a massive windfall for the wealthiest Americans and provide almost no relief to middle-class taxpayers who need it most,” Senate Minority Leader Chuck Schumer said at the Capitol.

Some Republicans, once fiscally demanding but now desperate for a legislative win after a year-long drought, shrugged off the spectre of adding billions to the federal deficit. Failure on taxes, after the collapse of health care repeal, could cost the Republican Party dearly in next year’s midterm elections with its House majority at stake.

“This is a now-or-never moment,” said House Speaker Paul Ryan, who built his reputation on tax and budget issues.

Likewise, Trump said in Indianapolis, “This is a once-in-a-generation opportunity.”

But the bitterly divided, Republican-led Congress faces critical decisions on eliminating or reducing tax breaks and deductions, with the Republican Party intent on producing a package without Democratic votes by year’s end. The last major overhaul in 1986 was bipartisan, and Trump was courting Democrats. One vulnerable incumbent, Indiana Senator Joe Donnelly, accompanied the president on his trip to Indianapolis.

Trump and the architects of the Republican plan insist that the overhaul is aimed squarely at benefiting the middle class and wouldn’t favour the wealthy. Still, a cut in the tax rate for Americans making a half-million dollars or more would drop by almost 5 percentage points as the wealthiest sliver of the nation reaped tremendous benefits.

Corporations would see their top tax rate cut from 35 per cent to 20 per cent. For a period of five years, companies could further reduce how much they pay by immediately writing off their investments. That’s all part of an effort that Trump said would make US businesses more competitive globally.

The plan would collapse the number of personal tax brackets from seven to three.

The individual tax rates would be 12 per cent, 25 per cent and 35 per cent – and the plan recommends a surcharge for the very wealthy. But it doesn’t set the income levels at which the rates would apply, so it’s unclear just how much change there might be for a typical family or whether its taxes would be reduced.

“My plan is for the working people, and my plan is for jobs,” Trump told reporters at the White House. “No, I don’t benefit. ... I think there’s very little benefit for people of wealth.”

Reopening the debate over economic inequality that rippled through the 2016 presidential campaign, the Republicans’ defence of the plan was met with scorn on the opposite side.

“President Trump’s tax plan is morally repugnant and bad economic policy,” said independent Senator Bernie Sanders.

In the absence of details on the plan’s cost, one back-of-the-envelope estimate by a Washington budget watchdog estimated the tax cuts at perhaps US$5.8 trillion over the next 10 years. The Committee for a Responsible Federal Budget, a non-partisan group that analyses spending and taxes, said Republicans had only identified about US$3.6 trillion in offsetting revenues, meaning the cost to the federal deficit could be in the US$2.2 trillion range.

That’s more than the US$1.5 trillion debt cost allowed under a tentative agreement by Republicans on the Senate Budget Committee – and the real battles will come as lawmakers quarrel over which tax breaks might be eliminated to help pay the balance.

The plan would nearly double the standard deduction to US$12,000 for individuals and US$24,000 for families. This basically would increase the amount of personal income that is tax-free.

Deductions for mortgage interest and charitable giving would remain, but the plan seeks to end most other itemised deductions that can reduce how much affluent families pay.

A battle is already brewing among Republicans over a move to eliminate the deduction for state and local taxes, which is especially valuable to people in high-tax states such as New York, New Jersey and California. Republicans from those states are vowing to fight it.

The plan also would:

–Retain existing tax benefits for college and retirement savings such as 401(k) contribution plans.

–Seek to help families by calling for an increased child tax credit and opening it to families with higher incomes. The credit currently is $1,000 per child. Also proposed is a new tax credit of $500 to help pay for the care of the elderly and the sick who are claimed as dependents by a taxpayer.

–Eliminate the estate tax – paid by those with multimillion-inheritances, a boon for wealthy individuals who inherit businesses, investments and real estate. Also slated for elimination is the alternative minimum tax, a supplemental tax for certain individuals, corporations and estates that enjoy exemptions that lower their income tax bills.

–Allow companies to pay substantially lower tax rates, part of an effort to make US businesses more competitive globally. The plan would impose a new, lower tax on corporate profits stashed overseas, and create a new tax structure for overseas business operations of US companies.

–Give new benefits to firms in which the profits double as the owners’ personal income. They would pay at a 25 per cent rate, down from 39.6 per cent. This creates a possible loophole for rich investors, lawyers, doctors and others; administration officials say they will design measures to prevent any abuses.