Donald Trump and Ted Cruz have tax plans likely to dramatically shrink the federal government.

If you think they can do that simply by eliminating waste, fraud and abuse, think again. If you think average Americans will benefit from these proposals, you should also think again, according to this new analysis by my Center on Budget and Policy Priorities colleague Isaac Shapiro.

Those at the top would get the most from the tax cuts and lose the least from the budget cuts to pay for them. And the budget cuts would have to be huge – because Trump and Cruz both say they want to cut taxes and also reduce the deficit.

Tax Policy Center

The chart compares the tax status in 2025 of people in households with at least $1 million of income with that of the bottom 80 percent of Americans ranked by income.

Millionaires are less than 1 percent of the population, yet they already enjoy nearly 15 percent of after-tax income. The bottom 80 percent, in contrast, get only a little over half of after-tax income.

Under the Trump and Cruz tax plans, the disparity would be even greater. Millionaires would get nearly 40 percent of Trump's tax cut, compared with less than a third for the bottom 80 percent. Millionaires would get almost half of Cruz's tax cut, compared with under a fifth for the bottom 80 percent.

The average tax cut and percent gain in taxable income for millionaires would be about $380,000 (17.9 percent) under Trump and $460,000 (21.6 percent) under Cruz. The middle fifth, in contrast, would get about $2,900 (4.9 percent of taxable income) and about $1,400 (2.4 percent) under Cruz. Even the bottom fifth would get a tax cut, though it would be only $169 under Trump (1.1 percent of taxable income) and $44 (0.3 percent) under Cruz.

If everyone gets a tax cut, what's the problem? Well, neither Trump nor Cruz explain how they'd pay for their tax plans. Spending programs are much more evenly distributed across the population than either candidates' tax cuts, as Shapiro explains. Thus, the lion's share of budget cuts would have to come from programs benefiting middle- and lower-income households and, for these households, the harm from the budget cuts would almost surely be larger than the gains from the tax cuts.

Forget claims that these tax cuts would spur enormous economic growth that would benefit people of all incomes. Though tax cut proponents proclaim otherwise, there's little to no evidence that tax cuts unleash such economic growth, and promises of benefits at all income levels are belied by decades of rising inequality.

Over the next decade, Trump would spend $3.2 trillion on tax cuts for millionaires while Cruz would spend $3.5 trillion, Shapiro reports. Suppose we actually had such sums at our disposal. Would tax cuts for millionaires be the best way to use them? The chart below suggests no. We would, for example, be foregoing the opportunity to make Medicare and Social Security solvent and double the resources devoted to medical research.

Tax Policy Center/Office of Management and Budget/Census/American Society of Civil Engineers

We don't, of course, face a budget future with projected surpluses that would let us choose between tax cuts and other priorities. We faced such a future in 2001, but President George W. Bush and Congress chose tax cuts over making Social Security and Medicare solvent or meeting other important priorities.