It's citizens do, directly to the IRS. You've never filled a tax return?

"Newsom is not suggesting people stop paying their taxes, said Tara Gallegos, a spokesperson for the governor. But she said the state is considering “whether there are potential options that would allow it to retain some of the funding it typically sends the federal government'.”
https://www.calonews.com/featured-topics/economic/could-california-really-withhold-tax-money-from-the-u-s-if-trump-cuts-federal-funds/article_69b1d3bd-44ca-4c99-a872-ca1b1dd7828d.html

After that all those individuals and businesses would still owe what they owe, only now with interest and penalties. It’s just a terrible idea that keeps getting repeated because it sounds “tough”

The administration has already been told by the courts they cannot withhold federal funds that have been appropriated by Congress. Do they care if they follow the law? Who cares about the frickin' law anymore?

But I also think businesses and individuals are concerned about federal funds being withheld from their state.

It’s just not a serious idea.

The courts will prevent Trump from playing these funding games.