IANAL but I know that a lot of companies when they lay people off give them various "parachutes" in the form of money and included are anti-disparagement clauses, that if broken you have to return the money.
And a lot of settlement cases could be argued to do the same thing. Using campaign money to do it might be illegal. Again, not a lawyer.
And then there's the whole "a DA can indict a ham sandwich" notion.
I don't pretend to know how this is going to shake out, but I've got my popcorn.
