Sen. Elizabeth Warren was among the economic justice advocates cheering Thursday after the U.S. Supreme Court upheld a tax on Americans with shares of certain foreign corporations—a win for the Massachusetts Democrat and other wealth tax advocates.

"Right-wing billionaires hoped an obscure legal case would blow up the tax code to avoid paying what they owe, but this effort failed at the Supreme Court," Warren said in response to the 7-2 ruling in Moore v. United States. "The fight goes on to tax the rich, pass a wealth tax on ultra-millionaires and billionaires, and make the system more fair."

Although the narrow decision doesn't explicitly affirm the constitutionality of federal wealth tax proposals from congressional progressives including Warren, court watchers had feared a ruling in favor of Charles and Kathleen Moore—a Washington couple who challenged the mandatory repatriation tax (MRT) in Republicans' 2017 tax law—would disrupt efforts to impose such policies.

The high court heard the case in December. Conservative Justice Brett Kavanaugh on Thursday delivered the majority opinion that the MRT "does not exceed Congress' constitutional authority." He was joined by Chief Justice John Roberts and the three liberals. Justice Amy Coney Barrett concurred in the judgment, joined by Justice Samuel Alito, who had faced calls to sit this case out.

Conservative Justice Clarence Thomas—who has provoked pressure to recuse himself from multiple cases or even leave the court by accepting and not reporting gifts from ultrarich Republicans—dissented, joined by Justice Neil Gorsuch. Thomas argued "the Moores are correct" that "a tax on unrealized investment gains is not a tax on 'incomes' within the meaning of the 16th Amendment, and it therefore cannot be imposed 'without apportionment among the several states.'"

The Roosevelt Institute and Institute on Taxation and Economic Policy (ITEP) warned in a September report that a decision siding with the Moores could have led nearly 400 multinational corporations to collectively receive more than $270 billion in tax relief.

"Today's ruling is a win for anyone who didn't shelter income in offshore tax havens before 2018," ITEP executive director Amy Hanauer said Thursday. "It preserves close to $300 billion of tax revenue paid by some of the biggest and most profitable corporations in human history."

"If the court had retroactively repealed this one-time tax, any other way of making up the resulting shortfall would have fallen far more heavily on middle-and-low-income families and small businesses," she added. "The Supreme Court also could have taken an activist turn of the worst kind by preemptively ruling federal wealth taxes unconstitutional today. To its credit, the court did not do so."

Groundwork Collaborative executive director Lindsay Owens similarly called the ruling "great news," adding that "next year, there is nothing standing in Congress' way to make the wealthy pay up."

Meanwhile, Morris Pearl, chair of the Patriotic Millionaires and a former managing director at BlackRock, had a more mixed response, saying that "we are relieved that the Supreme Court chose not to overreach in its Moore v. U.S. decision. The plaintiffs' patently absurd argument, based on incorrect and seemingly fabricated facts, threatened to upend the tax code and preemptively declare taxes on wealth and unrealized capital gains unconstitutional. The court chose not to do so."

"But we remain deeply alarmed for two reasons. First, it is now evident that four Supreme Court justices are enthralled by the influence of billionaires. In their concurring opinion, Justices Barrett and Alito asserted that unrealized capital gains cannot be taxed, as did Thomas and Gorsuch in their dissent, which said there is a realization requirement for income tax," Pearl said. "These justices have now signaled their intention to declare taxes on wealth and unrealized capital gains unconstitutional."

"Second, the Supreme Court should never have agreed to hear this case in the first place," he continued. "Billionaires are shamelessly buying influence on the Court. While seven Justices rejected this specific attempt by plutocrats to avoid their patriotic duty, this does not change the fact that several members of the Supreme Court have corrupt relationships with billionaire benefactors looking to purchase outcomes on the court."

This post has been updated with comment from the Patriotic Millionaires.

Republished from Common Dreams under Creative Commons (CC BY-NC-ND 3.0).