Regressiveness (A perjorative, but I'll let it go) in FICA is not all that unjust since the lower two income quintiles benefit disproportionately from it, in payments as well as in its treatment as taxable income. I really don't have a huge problem with regressive taxes, you can statisticize anything to show how disproportionate the impact on the poor or any other group may be, hence the perenniel jokes on our side about this, along the lines of "World ends tomorrow, women, minorities most affected!"
I am not totally opposed to a so-called 'Progressive' income tax scheme, unlike the flat-tax crowd, but the system we have is skewed too far in favor of transfer payments and does need to be broader if not flatter too. When over half the voters pay llittle or no net income taxes, and are in the position to continue jacking up the rates on the rest, they system is on a toboggan ride to Hell, that is an unsustainable situation. You may be too young to remember the legacy of the Carter years, but the 70% top income tax rate then essentially capped the level of effort people were willing to put into an endeavor, since after a certain point (A surprisingly low one, I might add, which affected even high earners in the trades) people just weren't willing to work for less than $.30 on the nominal dollar (Not even counting how much more that was reduced by State taxes and other non-income tax deductions).
Above the REAL poverty level (Not 'Basic cable' poverty) everyone needs to be a real stakeholder in the income tax system by being a net payer at some appropriate level. Failure to recognize this by the vote-whores of both parties in Congress will lead to a period of entitlement-taxation cycle tyranny ('Vox populi, vox Dei') which can only end in economic and probably social chaos.
