The Tax Policy Center has new numbers about the distribution of average tax rates by income class. Consider, in particular, the estimates of the combined income and payroll tax by income class; I’ve deleted a couple of columns to make the thing fit with more or less legible type:
Here’s how to read this: 40 percent of taxpayers with incomes between 30K and 40K pay more than 12.9 percent of their income in income and payroll taxes; meanwhile, 25 percent of people with incomes over $1M pay less than 12.6 percent of their income in these taxes. This suggests that there are a lot of very-high-income guys paying a lower tax rate than their secretaries.
And that doesn’t even take into account state and local taxes, which are quite regressive.
Taken as a whole, the US tax system is probably somewhat progressive — but not as much as you might think, especially at the upper end, and very erratically. There are a lot of rich people basically free-riding on the system.