The Constitution is explicit that the federal government’s power to tax and spend is assigned to Congress, not the president. But President Donald Trump — in a way unprecedented in American history — has ignored this basic constitutional principle and has arbitrarily cut off federal funding to myriad recipients. His actions are blatantly unconstitutional, illegal and unwise.

Recently, there have been reports that Trump is planning to dramatically increase his attempt to control federal spending by cutting off massive amounts of money received by California, including the University of California system, the California State University system and California Community Colleges. It is estimated that, together, they receive $7.3 billion annually.

California Gov. Gavin Newsom has responded to this threat, noting that the state pays $83 billion a year more in revenue to the federal government than it receives back.

“Californians pay the bills for the federal government. We pay over $80 BILLION more in taxes than we get back,” Newsom posted on X. “Maybe it’s time to cut that off.”

It’s not clear what this means because state governments do not pay taxes to the federal government; people and businesses pay their taxes directly to the United States. In theory, Newsom could try to lead an organized rebellion of people and businesses not paying their federal taxes.

Nothing quite like that has ever happened in American history, so it is impossible to know what the outcome would be. In 1791, the Whiskey Rebellion began: Farmers in western Pennsylvania refused to pay an excise tax on whiskey that the federal government imposed to collect revenues to pay off its Revolutionary War debts.

President George Washington personally led a militia of 13,000 troops to western Pennsylvania to put down the uprising. It ended quickly and the authority of the federal government was established.

There have been other major clashes between the federal government and the states, but nothing like what Trump is fomenting now. The best way to avoid a constitutional crisis is for federal courts to quickly and forcefully rule that the president has no authority to take over the spending power and cut off federal funds.

A lawsuit about this was filed in federal court in San Francisco on June 4; it is a class action on behalf of all of the researchers at the UC system who have had their funding arbitrarily ended since January 20. I am one of the attorneys on behalf of the plaintiffs challenging the Trump administration.

It is estimated that at UC Berkeley alone, one of 10 campuses in the UC system, the Trump administration and its Department of Government Efficiency have cut off $80 million of federal funds. Across the entire UC system, this is a staggering sum. This includes, for example, huge amounts of money that go for medical research.

It is unfathomable why Trump wants to cut research that finds ways to prevent and cure diseases; and it is inexplicable that he wants to cut funds into research that have made the U.S. the leader in technological advances.

The lawsuit on behalf of UC researchers explains why Trump’s actions are unconstitutional and illegal. When a federal law appropriates money, the president has no constitutional authority to refuse to spend it. The president, of course, can veto any spending bill. But once it becomes the law, either with the president’s signature or over his veto, the president cannot claim a new unchecked veto to refuse to spend federal money.

In the early ’70s, President Richard Nixon asserted the authority to impound funds and refuse to spend money appropriated by Congress. The federal courts, including the Supreme Court, concluded that the president lacked the power to do this.

In response, Congress, in 1974, passed the Impoundment Control Act to prevent presidents from refusing to spend funds appropriated by Congress. The law forbids the presidential impoundment of funds, but allows the president to propose revocations of money appropriated by federal law. If the president wishes to rescind spending, they must send a special message to Congress identifying the amount of the proposed rescission, the reasons for it and the budgetary, economic and programmatic effects of the rescission. After the president sends such a message to Congress, they may withhold funding for up to 45 days.

Trump’s cutoff of funds to University of California researchers has not followed this procedure.

The cut off of funds to researchers also violated the Constitution because it has been done without a semblance of due process of law. The actions by DOGE and federal agencies has additionally violated the federal Administrative Procedures Act in that, in the words of the federal law, it has been “arbitrary, capricious and an abuse of discretion.”

Our Constitution did not create a king. Quite the contrary, the framers of the Constitution were deeply distrustful of executive power because of their experiences under the rule of King George. No president in history has asserted the ability to control federal spending as Trump has done. The federal courts must stop this if we are to remain a democracy under the Constitution.

Erwin Chemerinsky is dean and professor of law at the UC Berkeley School of Law.