Establishing a wealth tax based on the rolling 10 prior years worth of PAC donations would feel somewhat fitting. A basis point per $50k or something.
Maybe donations to political parties could be just taxed at 200% (technically ~76% but 200 sounds better)?
To give a million to any party you have to pay 2 in tax.
You could just tax political donations or political ads. I'd suggest 50% federal tax, 25% state tax, and 25% local tax.