Sunday night, Rep. Alexandria Ocasio-Cortez, D-N.Y., appeared on “60 Minutes” to promote her policy agenda, including a so-called “Green New Deal.” According to Ocasio-Cortez, the easiest way to pay for her deal is to raise individual income tax rates. She suggested that individuals with incomes at the “tippy-top,” defined as $10 million in income, should pay a 70 percent tax rate, a rate not seen since the beginning of the Reagan administration.

There are a litany of issues with this sort of proposal.

First, it’s important to realize that when marginal tax rates reached 70 percent, or higher, few individuals, if any, actually paid those rates. Effective tax rates, meaning what individuals really paid, were much lower. A paper from 2017 by Thomas Piketty, Emmanuel Saez, and Gabriel Zucman — the same individuals that have estimated that a 70 percent rate would be ideal — found that effective tax rates were much lower, around 40 percent. When tax rates reached their peak at 91 percent in the 1950s, the effective tax rate on the top 1 percent was 42 percent.

But that includes all types of taxes. Even with those exorbitant marginal rates, their effective income tax rate was only 16.9 percent.

Ocasio-Cortez is missing a key part of the equation. Comparing tax rates across time isn’t always an apples-to-apples comparison. Over the last 50 years, we’ve moved to lower tax rates and broader tax bases, following the advice of decades of economic analysis. While the headline rates are lower, we’re taxing more types of income. In fact, effective tax rates on the wealthy were 36.4 percent in 2014 — only slightly below where they were in the 1950s. This idea would reverse the trend.

By raising rates that high today, individuals would seek to limit their tax liabilities through shelters and tax games. For example, very few individuals have wage income above $10 million. Save for a few actors and professional athletes, the bulk of income at this level is from capital gains or business income. Jeff Stein, writing at the Washington Post, argued that this proposal would raise $750 billion over the next decade, but that is highly unlikely. Without a complete overhaul to the taxation of capital gains, wealthy investors would move to limit their capital gains realizations to avoid this absurdly high rate.

In reality, very little money would be raised by the proposal.

Such a high tax rate would also encourage high-income individuals to shelter their income in other ways. Currently, corporations pay a 21 percent income tax rate. Smart individuals and their tax planners would find any way possible to move income into the corporate structure to limit their tax liability.

This idea also makes other tax provisions more valuable. Currently, a high-income individual saves 37 cents for every dollar that they donate to charity. Under Ocasio-Cortez’s proposal, they’d save 70 cents for every dollar donated. Charities, not the Treasury, would be a large beneficiary, particularly for individuals who are very close to the $10 million rate increase. The same could be said of other provisions, such as the exclusion for employer-sponsored insurance.

Not to be outdone, Julian Castro, a former San Antonio Mayor and likely 2020 presidential candidate, on Sunday proposed that a 90 percent rate could be an option, harking back to the 1950s.

Raising the income tax rate to 70 percent or higher would be a tremendous misstep for the federal government and taxpayers, with the only beneficiaries being high-priced accountants and attorneys.

Nicole Kaeding (@NKaeding) is director of federal projects at the Tax Foundation.