Treasury Secretary Steve Mnuchin, in remarks Wednesday, channeled Trump's penchant for exaggeration.
The headline of the administration's one-page, double-spaced release made the same claim.
Spicer was asked about 401 (k) accounts in particular, following remarks Wednesday by Trump's National Economic Council Director Gary Cohn, who said "homeownership, charitable giving and retirement savings will be protected".
So how ambitious is it? According to the Congress's own Joint Committee on Taxation, it will reduce federal revenue by $2 trillion over 10 years. That assumes all elements of the plan are approved by Congress, which is doubtful.
"Let me say, this isn't about President Trump's tax returns", Mnuchin said.
Will the plan raise taxes on the wealthy? The alternative minimum tax is meant to prevent high earners from being able to avoid all income taxes but can also affect middle-income taxpayers.
"It's kind of interesting to see how Trump was elected on this kind of anti-establishment basis", financial policy analyst Daniel Sankey told Radio Sputnik's Brian Becker. The group advocates for deficit reduction as a pillar of economic growth. After a series of tax cuts and the worst economic downturn since the Great Depression, he left office with an annual deficit of $1.4 trillion.
The administration wants to reduce the number of tax brackets to three from seven, but it has yet to determine the income levels for people who would be put in each bracket. But Cole forecasts growth would increase by only half that amount, resulting in ballooning deficits.More news: Marchers use Trump's 100th day to protest climate policies
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Right now, that's not an option for Trump's tax plan.
But Democrats are attacking the plan.
The estate tax, for example, only kicks in for Americans inheriting more than $5.49 million from a deceased loved one. "We have no idea what deductions he's taking; whether he's still paying the alternative minimum tax".
Mnuchin also wouldn't rule out the possibility that the plan may provide an absolute tax cut for rich people - something he explicitly promised would not happen during his confirmation hearing.
The administration says it would ensure that wealthier Americans wouldn't exploit the lower pass-through rate, but it provided no details on how that would do so. Under the proposal, married couples filing jointly would not owe income taxes on the first $24,000 of income (up from $12,600).
"I can't make any guarantees until this thing is done and on the president's desk", Mnuchin said.
Associated Press writer Josh Boak contributed to this report.
"While lowering rates is our goal, the reality is that hammer just might whack one of the few areas where many middle class homeowners get a break on their taxes", Pascrell said in a statement.