The marriage penalty arises invisibly from progressive rate brackets

Evidence

So as the system evolved, a mostly white male Congress introduced a “marriage penalty.” When certain couples got married, not only would they not get a tax cut but their taxes would increase when compared with what they would have paid by remaining single. How this happens is hidden in plain sight in the rate structure. — Dorothy A. Brown, The Whiteness of Wealth, 120

Categorization

• DEFINE: Defines ‘marriage penalty’ precisely and flags that its mechanism is hidden in the rate structure itself — core definitional scaffolding for the reader’s argument.