As I see it, the value in a wealth tax isn't just in a cash grab. It's about reining in the behaviour of the wealthy.

If you can cap individual wealth to eight or maybe nine figures, you take options like "bankroll major state/national elections on a whim" and "buy up major media and communications brands" off the table. As far as I'm concerned, these are things we can do without and probably have a healthier society as a result.

California's attempt might be well-intentioned, but it seems so weaksauce that it won't reach to the behaviour-modifying level.

The "why bother investing" mentality that's used to argue against Georgist land-taxes might be interesting applied to a high wealth tax too. If your stock portfolio is already approaching the cutoff line, will you press as aggressively for that last short-term bubble with long-term expenses?