Quote from ArchAngel:
Absolutely true - as far as the statistic goes. In absolute dollars paid, the richest few % pay the largest % of total tax dollars.
However, a factor missed by that simple (albeit correct) statistic is that the richest few % pay less % of their total income in income taxes than those in the more middle income range. That's probably the more salient point.
A reasonable flat tax (even if it's a 3 or 4 graduated levels) on all income with no deductions or credits or preferences to how you make or spend your money seems like would void most or all arguments.