As the United States heads toward running out of cash in a few weeks, here's a reminder how this happened:

* The law says what tax rates are, determining revenue.
* Each year laws are enacted that direct money to be spent a certain way.
* Existing debt has to be serviced (e.g. bonds).
* An older law limits national debt.
* Republicans drove up the debt during the Trump Admin (tax cuts, airline bailouts, etc) so that the limit is about to be reached.

The laws are logically incompatible.