Interesting discussion here about income tax versus consumption tax. As a Swede I feel the customary compulsion to jump in to explain to the world how it works here, and why everyone should do it our way.
I think many people here on gaf would want a Scandinavian-type welfare system, with public healthcare, over a year of paid parental leave and free education. What many of you don't seem to realize, is that to be able to afford Scandinavian-type welfare systems, you don't only need Scandinavian tax rates (they are much higher in Scandinavia than in the US) but also Scandinavian tax brackets. The top marginal income tax rate in Sweden is around 56.6 % (with slight variations depending on the rates for local government where you live) and I think many here would support that, but you also have to be aware that the top tax bracket that gets this rate starts at annual incomes of around $65000. We also have a value added sales tax (consumption tax) at 30 % (though with much lower rates for certain things, such as food)
As a social democrat (by ideology, I don't vote for them though because the social democratic party is too watered down at the moment; this is ok, though, because we have proportional representation, so my vote isn't wasted), I still think it's worth it, but you have to be aware of the implications of the policies (you think) you support.
I think American top tax rates should be increased even though that alone would not be nearly enough to pay for a Scandinavian welfare system. Increasing the top rates is necessary just in and of itself in order to combat your democratic issues of having a way too wealthy class, which has the economic means to far too heavily influence policy.
I realize that changing to a Scandinavian-type tax system would need to take a VERY long time, as the current situation for the working class and lower middle class in America is bad enough that it would be impossible for them to survive such sweeping changes overnight. The situation for them would need to improve significantly before such changes become feasible.
TLDR: Democratic socialists (and their leaders) in the US need to temper their expectations, and eventually accept and embrace the fact that you can't pay for universally free (well with some nominal fees to discourage waste) healthcare, free education and dignity-allowing income security only by squeezing the rich. That is a good thing to do in and of itself, but to be able to pay for all that good stuff, nearly everyone needs to contribute. It is a requirement for democratic socialism.
Also, I agree with darkace that the biggest problem in the USA is not an insufficiently progressive tax code, but rather far too small redistributional systems. In order to be able to afford Scandinavian style redistribution, you need a tax system that is far less progressive than the current system (in terms of how big a share is paid by the richest parts of the population). The gains are well worth it though.