[prostoalex]

US tax system is based around tax events, i.e. triggers, which require a transaction to take place. Unlike other economic systems, money sitting quietly will not be taxed until it kicks off a dividend, pays interest or changes hands thereby triggering capital gains.

Outside of municipal property taxes there's currently no framework for taxing wealth. An extreme theoretical case would be a billionaire with nothing but a savings account earning 0%. Under current system, he could while away indefinitely, making small withdrawals here and there to cover the lifestyle, while generating 0% tax burden.

Which is why discussing income taxes is a red herring - at this point people generating eight-digit incomes choose to work, and have a rather nice and comfortable way out if/when they decide to "spend more time with the family".

Wealth tax is a third-rail for either party, as majority of donors on both side are wealthy, but not necessarily high-income individuals.