I'm of the opinion that politicians above a certain level (in the UK: prime minister, members of Parliament and maybe mayors) should just get a permenant annuity for the rest of their lives on the condition that they can't make money from anything else, ever. No stocks, no "speaking engagements" or do nothing bribery jobs. It would be expensive yes, but cheaper than the cost of corruption. Maybe have the value of the annuity be based of rank, MP gets 300k/y and PM gets 500k/y.
Appreciate the British perspective. I don’t think that would work in the US; the people at the top are the rainmakers for their parties, and the party will take care of them somehow. Rather I think it’s more interesting in a knowledge economy to use the money printer to move talented people into public service who otherwise would’ve wasted their lives in the private sector positioning themselves as close as possible to the money printer (while also setting a high floor price for their services).