Equal total income across a household produces unequal tax burdens

Evidence

After law school, I spent a couple of years working on Wall Street as an investment banker. My income was around $75,000—roughly equivalent to my parents’ combined incomes—but when I compared our tax payments, I always came away thinking they were paying too much. It didn’t make sense; what I had been taught about our progressive tax rate system was that the more money you make, the higher the tax rate that applies to your income. It is based on a concept called “ability to pay”: If you have more, you should pay more. Each of my parents made half of what I did, so I should be paying much higher taxes than my parents. The numbers did not add up, and in my mind numbers never lied. — Dorothy A. Brown, The Whiteness of Wealth, 21

Categorization

• QUESTION: This is the puzzle that drives the book — need to understand how the same earned income split across spouses vs. one earner produces different tax outcomes.