Looks at tax revenue vs GDP. No matter the tax rates, the percentage stays the same (fluctuations within a couple points) regardless of official tax rates.

When you increase taxes on the wealthy, they don’t pay more. They either pay for loopholes to be created or they reduce/stagnate salaries to compensate.

Meanwhile, Congress cares more about who pays them than who votes (there’s a reason they argue about superficial stuff and agree about all the worst stuff).

When all the taxes get paid by the rich, the poor lose that influence and still wind up making the same amount of money anyway.

Universal sales tax is better. If the rich buy more stuff they pay more. There’s no loopholes to be found. You can also provide tax breaks to the poor by reducing or eliminating sales tax on consumer goods which greatly affects the poor, but only marginally affects the rich.