Completely unconstitutional. The (then new) income tax required a constitutional amendment.
Not to mention impractical with a diminishing rate of return per year if you just take 2% of someone's wealth. "Wealth" is also not cash assets in many cases.
What is really needed is a HFT tax on the hedgies who trade in and out of a position. They work to destroy the small investor. A HFT tax should be on any trades that purchased and exited within a 30 day period of time.
Most HFT trading is just in / out /in/ out over and over again. Charge $.01 or $.02 per share tax collected will be able to reduce the deficit.
HFT = High Frequency Trading.