since education is a good thing. As your link goes on to say:
Some examples include gas tax and cigarette tax. For example, if a person has $10 of income and must pay $1 of tax on a package of cigarettes, this represents 10% of the person's income. However, if the person has $20 of income, this $1 tax only represents 5% of that person's income.
Sales taxes that apply to essentials are generally considered to be regressive as well because expenses for food, clothing and shelter tend to make up a higher percentage of a lower income consumer's overall budget. In this case, even though the tax may be uniform (such as 7% sales tax), lower income consumers are more affected by it because they are less able to afford it.
Since income tax is worked out on a person's income, the situation of its base being "a higher percentage of a lower income consumer's overall budget" cannot arise - it
is the budget. So, for instance, a UK taxpayer who earns £150K pays:
(20%*£37,400)+(40%*(£150,000-£37,400))=£7,480+£45,040=£52,520, or 35.013% of their taxable income
Earning £200K, they pay £52,520+(50%*(200,000-150,000))=£77,520, or 38.76%
Earning £400K, they pay £53,520+(50%*(400,000-150,000))=£177,520, or 44.38%
and so on. The percentage paid will increase with income, approaching 50% as more and more of their income falls in the 50% bracket, but never quite reaching it. That is why it is not 'regressive'. At most, you can say the rate is flat above £150K. But, as I say, that's the top 1% of earners - not, I would suggest, the 'upper middle class'.
How much less, would your income tax rates bring in? If you want to be able to use them as an example, you ought to try to work this out, roughly - get hold of some statistics for the distribution of income among Americans and make an estimate. Then you'd know if the defense cuts (which sound pretty sensible to me, with or without changes in the income tax system) would offset them.