This is an archived article that was published on sltrib.com in 2017, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.

Washington • President Donald Trump's plan to overhaul the nation's tax code could provide significant tax cuts for the working-class voters who elected him, but the unknowns could end up hurting many of these core supporters of the president.

A look at how Trump's tax plan could affect families at different income levels:

The working class • These are the people who have been left behind by an increasingly globalized economy.

Trump's proposal, a one-page outline short on detail, says he would double the standard tax deduction, which could provide significant relief to working-class families. But Trump's top economic adviser used some bad math to describe the proposal, raising questions.

Gary Cohn said the standard deduction for a married couple would be doubled to $24,000. But that's not double. The standard deduction for a married couple is $12,700, so double would be $25,400.

Cohn said the deduction would create "a zero tax rate for the first $24,000."

That sounds great, but very few families making $24,000 a year pay federal income tax, said Roberton Williams, a fellow at the nonpartisan Tax Policy Center. In fact, 44 percent of U.S. households pay no federal income tax, though most pay other taxes.

Trump's sketch is silent on whether the tax code would still include the personal tax exemption, which allows most families to exempt $4,050 in income for each spouse and dependent child. In big families, this tax exemption can add up.

The middle class • The median household income in the U.S. is about $55,000, though people living in high-cost areas can make much more than that and still feel like they are in the middle class.

Doubling the standard deduction — or at least raising it to $24,000 — could provide significant tax relief to middle-income families. But whether they pay more or less depends largely on details that have yet to be released.

One of those pesky details is how Trump will structure the tax rates on individual income.

Trump has proposed reducing the number of tax rates from seven to three — 10 percent, 25 percent and 35 percent. But the administration has yet to determine the income levels for people who would be put in each bracket.

High-income families • Trump's plan has the potential to provide big tax cuts to high-income families — unless they live in states with high state and local taxes.

Trump calls for eliminating the Alternative Minimum Tax, which was enacted in 1969 to prevent high-income people from paying no income tax. It has evolved over the years and now affects about 5 million households, most of them making between $200,000 and $1 million a year.

In 2005, Trump himself paid $36.5 million in taxes, mostly because of the AMT. Without it, he would have paid $5.5 million, according to a leaked copy of that year's return.

On the flip side, Trump wants to eliminate the deduction for state and local taxes, a big tax break that benefits millions, especially people living in Democrat-controlled states with high local taxes such as New York, New Jersey and California.

Last year, more than 43 million families claimed the deduction, saving them nearly $70 billion.