Just as Americans are gearing up for tax season, the 2020 presidential election race is starting to kick into high gear. Candidates are declaring their intentions to run and discussing their views on the best course for the nation.

Democrats have largely opposed the tax policies that their Republican counterparts have enacted over the past two years, and many are looking at ways to reverse the rising levels of wealth inequality among the U.S. population. Two candidates, Sen. Elizabeth Warren (D-Mass.) and Rep. Alexandria Ocasio-Cortez (D-N.Y.), recently made tax proposals seeking to increase the tax burden for wealthy Americans. Below, you'll get the details on the two proposals, with an eye toward learning what they have in common and how they differ.

Clockwork gears in metal, with the words "Tax Reform" engraved on the side.

Image source: Getty Images.

The AOC proposal

The Ocasio-Cortez proposal centers on the income tax. The proposal is relatively simple: take the existing tax brackets and add an eighth one for the highest-earning taxpayers. Instead of the current 37% tax rate applying to all taxable income above the specified top limits -- currently between $300,000 and $600,000 depending on filing status -- the 37% tax rate would only apply on taxable income up to $10 million. Taxes on the first $10 million of income would therefore remain the same, but for every dollar above the $10 million threshold, a new top marginal tax rate of 70% would apply.

The Ocasio-Cortez proposal would be a simple change to make from an administrative standpoint. No other changes to tax laws would be necessary, and existing rules for determining income, deductions, and credits would remain unchanged. There's precedent for marginal tax rates of 70% in U.S. history, so the proposal should easily survive any legal challenge on constitutional grounds.

It's unclear exactly whether the proposal would lead to higher revenue for the federal government. Taxpayers would take steps to adapt to the new tax scheme, seeking to keep their taxable incomes low enough to minimize any income that would be taxed at the 70% rate. According to initial analysis of the proposal from the Tax Foundation, restricting the new 70% bracket to ordinary income would be the best way to raise revenue, and in that case, it estimates $189 billion in net new revenue over the next 10 years. By contrast, if the proposal applied to all income, including capital gains, the Tax Foundation believes that it would actually reduce revenue by $63.5 billion over the same decade. That's because most investors can time when they sell assets that have risen in value, indefinitely deferring most capital gains liability.

The Warren proposal

The Warren proposal, on the other hand, has nothing to do with the income tax. Instead, it would impose a new tax based on a person's wealth. Those with assets worth more than $50 million would pay a 2% wealth tax on the amount by which their net worth exceeded the threshold. A higher tax rate of 3% would apply to those whose wealth exceeded $1 billion.

According to proponents of the proposal, the wealth tax could generate extensive amounts of government revenue. Estimates put the impact at $2.75 trillion over 10 years, with about 75,000 households being subject to the tax.

However, the Warren proposal has some additional complications. As a brand new type of tax, the wealth tax would require a new bureaucratic apparatus to collect information on taxpayer wealth as well as collecting and enforcing the tax itself. There's a debate about whether the wealth tax would be constitutional, as the constitutional amendment that specifically allows taxes on income doesn't mention taxes on wealth. Yet the federal estate tax has been upheld constitutionally despite its starting point of the value of a decedent's assets, and taxpayers are intimately familiar with the many personal property and real property taxes that many state and local jurisdictions impose.

Some critics have also noted that the wealth tax could spur a new resurgence in wealthy Americans renouncing their U.S. citizenship in an effort to avoid taxation. Such activity has moderated quite a bit since the early 2010s, when some high-profile investors chose to emigrate permanently to avoid foreign financial reporting requirements and capital-gains taxes on stakes of companies going public. But with billions at stake, many high-net-worth Americans might seek friendlier jurisdictions elsewhere. The Warren proposal does seek to impose a penalty tax on those who'd be subject to the tax and renounce their citizenship. But it's unclear how far back into the past such a provision could get imposed retroactively, and if wealthy people see the odds of the proposal's passage increasing, they'd likely take preemptive action to try to escape the tax.

Let the debate continue

Regardless of your own views on these tax proposals, they both aim to extend the debate over wealth inequality and how to address it. There's no chance that either of these proposals will move forward until 2021 at the earliest, but they do represent aggressive platforms that more moderate lawmakers on both sides of the aisle could use as starting points toward finding eventual compromise positions.

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