Rather than tax personal or corporate income, We tax the electronic movement of money.
Most of our money transactions are electronic.
A very small percentage are cash.
We can ignore the cash and concentrate on the electronic.
Every time an electronic transfer of funds takes place, simply take a percentage off the top.
The system is already in place, to record transactions and collect and remit funds.
Our banks and credit card companies have been doing it for years.
This may be 1, 2, 3 or more percent, depending on what the current needs are.
There would be no loopholes.
The only exception would be transfers, of the collected funds, TO the government.
This idea will catch on with the rest of the world as they realize that they can collect their taxes automatically.