The case before the justices Tuesday could have sweeping implications for the U.S. tax system and derail proposals from some Democrats to create a wealth tax.

The Supreme Court on Tuesday is hearing oral arguments for Moore v. United States, a case that could affect broad swaths of the U.S. tax code. The case involves a Washington couple who own a controlling interest in a profitable foreign company affected by a tax enacted via former President Donald Trump’s 2017 tax overhaul.

Oral arguments in a closely watched case before the court could signal whether the justices intend to rein in Congress’ power to tax income.

In Moore vs. U.S., a sweeping decision that sides with the government could 'super-charge the political drive' for a wealth tax, one expert said.

The Supreme Court’s decision could upend the nation’s tax code at a time when the Biden White House is seeking to raise taxes on the richest Americans.