The problem with a concept like "fair share" when it comes to taxes is that there really is no accepted definition.
For some, any tax on themselves is not fair. They should get a free ride and the only thing they have to do is fill in the blank or the reason why.
A-I don't make much money
B-I have many expenses
C-I wasn't born here.
D-I got a bum rap as a child or my ancestors were blank.
Etc etc.
These same folks may also fit into the mold whereby the
"rich" or well off can't ever pay enough to be "fair".
So, with Bill Gates, he should have been at taxed at a 95% of income for example.
To others, fair means the same. For example, a Value added tax or a flat income tax...
As Paul Simon once wrote, "a man hears what he wants to hear and disregards the rest!"
