In 1970 a bill was passed that required all congressional votes to be recorded, even Committee of the Whole. This was uber bad because now that a representatives vote was public record, it could be so easily sold..
There is a lot of good evidence in this talk, however this is 2019 and I believe nothing that people tell me without independent verification! So I want to validate this all as actually legit.
But, either way, I can see that if a representatives vote was not a matter of public record, they couldn’t run to their corporate overlords and prove they voted a certain way.
There is a person that is constantly fighting Bar associations and others to get legal, public copies of laws. Noting here, so when I have time to look them up; they have a lot of experience fighting this for decades, and they can explain how selling records works.