What if we taxed what people spend, not what they earn?

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When people talk about tax fairness, the focus is almost always on income. How much the rich earn, how heavily that income should be taxed, and how to make sure lower earners are protected. But there is an older idea that is quietly starting to get attention again. What if taxes were based not on what people earn, but on what they spend?

This is more than a technical tweak. A progressive consumption tax – where people who spend more face higher effective rates – can...