The ultimate wet dream is a direct wealth tax, but that would create howls of protest. Indirect taxes can accomplish much of that, but only slowly. So, we have the inflation tax (does anyone believe inflation is really under 2%, and even if it is, bond interest after taxes and inflation is negative). Another route is to mess with tax shelters that exist under law--restrict IRA distributions, increase penalties, go after 529 plans. That's the current tack that's being taken.
Another way to do it is by restricting retirement savings options--such as the myIRA family of plans, or the idea floated around to force IRAs and pensions to invest only in "safe" government bonds so the plans wouldn't be subject to market fluctuations (or the possibility of private growth, either).
No word on taking her trust funds.