A big wealth tax would cause wealthy people to sell stocks, bonds, or property to raise cash to pay the taxes. Markets with forced sellers and no buyers tend to collapse. How about a smaller wealth tax? Well, other countries have tried them and are abandoning them.
Taxing wealth is the same as taxing saving and investment (actually, it’s the same as triple- or quadruple-taxing saving and investment). And that’s bad for competitiveness, growth, and wages.