You wouldn’t even need to use cash. Just have the politician buy a penny stock, bid up the price with illicit money, and let him sell at a profit. Commodities, jobs, contracts, speaking fees, book sales all of which are perfectly legal can be used to pay off a politician.
The Left argues that we need big government to help the little guy, yet all of history from the dawn of time shows that government is a tool of the wealthy and politically connected to control the little guy. Why can’t they learn?
Yes. Trusts and foundations that receive donations that, I believe, are the pol's own money coming into daylight. Partnerships that pay x million a year for no duties... which I again suspect is the pol's own money laundering its way back into daylight. And as you say, consulting fees for no obvious work, gazillion dollar book advances for books no one reads... (and I suspect aren't even printed in the numbers claimed...)
The hardest thing about retiring from a life of public service is bringing your money into daylight in a way thats believable.
When I see a politician suddenly with several hundred million in the bank (that we know of) I always remember that no one bribes an ex-president or an ex-senator.