It's hard to imagine it today, but in the early 20th century, proposals to cap personal wealth and income were fairly common — particularly among congressmen who considered themselves socialists. With the passage of the 16th Amendment in 1913, however, these lawmakers had better tools for addressing income inequality. That amendment gave the federal government the right to impose an income tax, so legislators could simply raise taxes on the wealthy in an effort to even out incomes.
Interest in wealth and income caps returned during the Great Depression, when unemployment skyrocketed and the gap between the rich and the poor became alarmingly wide. That's when Washington Rep. Wesley Lloyd introduced an amendment to cap annual incomes at $1 million. His colleague, Rep. John Snyder of Pennsylvania, followed Lloyd's proposal with an amendment of his own that would limit investment income.
Those amendments never got enough support to move them out of Congress, but who knows — given the widening gap between the rich and poor today, we could very well see similar proposals again [source: Vile].