It’s only a bill of attainder if you consider paying a tax a “punishment”. SCOTUS could flop either way on this. If they declare a tax is a punishment it would open the doors to many other actions. I’ll bet they let it stand.
One aspect they may not be able to overlook is the effect this will have on Employer/Employee contracts. Even if they don’t see the tax as some sort of punishment, if they don’t honor our system of contracts we have NOTHING.
The top federal tax rate is 38%. 90% is a punishmnt if others making similar amounts are not taxed at the higher rate.
I guess it’s that old standby—we’ll have to “punish” them at the polls.
The trouble is, as the general population gets stupider and stupider, that gets harder and harder to do.