How has it survived this long when we should have “equal protection” under the law. It boggles my mind the mental gymnastics that had to be used to get around that.
Probably because the income tax is segmented. Everyone pays the same tax on their first $50,000 or whatever. It’s only the higher bracket of income subject to the higher tax. So no one is charged a different tax on the same portion of income.
If they said all your income is taxed at a higher rate if the total exceeds a certain limit, then you’d have a better equal protection argument. That’s when you’re singling out an individual for different treatment, not singling out the income itself for a different tax.