The fate of a national wealth tax may ultimately hinge on a few words buried in one of the Constitution’s most controversial passages, right alongside the notorious “three-fifths compromise.” Besides serving as a reminder of the country’s shameful history of slavery, the so-called enumeration clause includes an important provision on taxation that has been disputed since the earliest days of the republic due to its vague requirement that “direct taxes” be “apportioned” according to the population of each state. Today “apportionment” is mostly associated with the distribution of congressional seats based on state population sizes, which is perfectly logical. In contrast, the apportionment requirement for “direct” taxes is perfectly illogical and has been rightly described by one tax scholar as a “constitutional absurdity.”

In her recent book on the history of taxation in America, The Price of Democracy, Vanessa S. Williamson describes the tax apportionment provision as an “ill-considered vestige of the requisition system and the three-fifths compromise” and unpacks the practical implications of the clause. “Under this apportionment system,” Williamson writes, “the federal government would determine a total amount of revenue a tax was supposed to raise, and then assign each state a share of the tax responsibility based not on the amount of the taxable item in each state, but on the state’s population.”

As Williamson goes on to note, none of this makes a lick of sense, and there is “no earthly reason that tax rates should have anything to do with state population.” While constitutional scholars disagree on the actual meaning of “direct taxes” (the founders themselves also disagreed and left it undefined), it was primarily associated with land or property taxes during the country’s first century. Then, in 1895, the Supreme Court decided to dramatically broaden its definition in order to strike down a modest 2 percent income tax that Congress had passed a year earlier. That controversial decision broke with the precedent of the 1860s, when the income taxes passed during the Civil War were tacitly approved by the high court.

The major change in the decades between, notes Williamson, was not precedent but the “ideological tenor” of the court, which by the late Gilded Age had become increasingly conservative and pro-business. The Court’s 1895 decision on the income tax marked the beginning of a forty-year conservative reign, remembered as the Lochner era, when the court regularly struck down labor regulations, minimum wage laws, and other progressive or pro-worker policies. The landmark decision also spurred a popular movement that culminated in the 16th Amendment, which explicitly grants Congress the power to levy taxes on incomes “without apportionment among the several States.”

In our own Gilded Age, the ideological orientation of the high court has once again shifted to the right and is now the most conservative it’s been since the Lochner era. This makes it highly likely that a simple national wealth tax would be struck down under the apportionment clause.

While the Constitution “clearly and unambiguously grants Congress the power to legislate an apportioned wealth tax,” University of Missouri tax law scholar David Gamage told Jacobin, a “non-apportioned (uniform) wealth tax” is a “contested question that is more complicated.” Steve Wamhoff, federal policy director at the Institute on Taxation and Economic Policy (ITEP) and former senior tax policy analyst for Sen. Sanders, echoed this sentiment, noting that it’s technically true the Supreme Court “would not say any and all federal taxes on wealth are unconstitutional,” but that they are likely to interpret it as a “direct” tax, in which case it would have to be apportioned by population. This would effectively “rule out the kind of straightforward federal wealth tax proposed by people like Sen. Elizabeth Warren and Sen. Bernie Sanders.”

There may be ways to get around this constitutional roadblock. Scholars like Gamage have designed proposals that specifically attempt to satisfy the apportionment requirement and thus reduce the constitutional risk. These proposals require taxing poorer states at higher rates and adding a mechanism to equalize the fiscal burden later based on wealth, typically through federal block grants and state tax refunds. While these proposals are “a little complicated and a little more difficult for the public (or frankly the typical lawmaker) to absorb,” said Wamhoff, “it could be done.”

Another option that might hold up slightly better under constitutional scrutiny is a tax on unrealized gains or a “mark-to-market” tax. This approach would capture the rapidly expanding wealth of oligarchs like Elon Musk and Jeff Bezos, which currently goes almost entirely untaxed because it is “unrealized” (something the ultrarich are careful to preserve, often taking out low-interest loans in perpetuity to avoid selling shares). An unrealized gains tax can be plausibly claimed to be an income tax, which would eliminate the apportionment requirement. According to Wamhoff, a mark-to-market tax would “logically be more likely to survive a constitutional challenge because arguably unrealized capital gains are a type of income and not wealth.” Yet a tax on unrealized gains would fare only marginally better before the current court, as four justices have already signaled that they view such a levy as a direct tax on wealth rather than income.

In the end, any serious attempt to tax the ultrarich will face significant hurdles regardless of what kind of adjustments are made in a potentially futile effort to accommodate conservative justices. A national wealth tax on the ultrarich commands consistent majority support in polling, which reflects its intuitive appeal and simple premise — neither of which survives the apportionment fix. The case for accommodation rests on the assumption that the Supreme Court can be satisfied. If it can’t, advocates of a wealth tax may be better off pushing for the most ambitious proposal and forcing the court to own the political consequences of striking it down.

As some have pointed out, there can be “unexpected consequences” when the judicial branch oversteps and strikes down laws that are broadly backed by the public. The court’s decision to rule an income tax unconstitutional in 1895 is a case in point. Not only did it undermine the court’s legitimacy with the public, but it also prompted a national campaign to amend the Constitution, which triumphed less than two decades later.

In his acclaimed history of the income tax in the United States, Steven Weisman described the Supreme Court’s ruling as one of the key decisions in the late nineteenth century that “laid the groundwork for the popular revolt against conservatism characterizing American politics” over the next two decades.

For obvious reasons, any wealth tax push should be paired with broader tax reforms and increases that don’t carry the same constitutional risk. This includes hiking the corporate tax and top income tax rates, eliminating loopholes that enable big companies or hedge fund billionaires to pay lower rates, closing the so-called Angel of Death loophole that erases all unrealized gains upon the death of a shareholder, replacing the estate tax with an inheritance tax, and much else. A wealth tax is the logical centerpiece of any program aimed at taxing the rich, but the broader arsenal of tax reforms provides an important bulwark against judicial overreach.