The Republican budget eliminates taxes on dividends, capital gains, interest, and inheritance.

[Zynx]

Quite simply put, these are rich people's sources of income overwhelmingly. While many people have some amount of these sources on their tax returns, they certainly never constitute a majority or anything even close to it. For the very wealthy, this would exempt from taxation nearly all of their income. In conjunction with a 25% top marginal tax rate for wage income, this would push the effective tax rate for the very high income earners well below the effective taxes paid by nearly everyone else. It is staggering just what this one means and it is a perfect hammer to bludgeon the Republicans with.