Because there were stringent laws against lobbyists directly influencing federal legislators with things like lavish vacations, expensive meals. nice gifts and so on, the Koch network focused on state legislators in the various states, since there are no analogous laws about not bribing them. An organization like the American Legislative Exchange Council drafts model laws like Stand Your Ground, that are distributed at legal corporate/legislator party vacations paid for by the dark money donors of ALEC.

Fast forward 40-50 years, and Robert Reich gives you a succinct picture of how American autocrats have seized control of a majority of the state legislatures and a 6-3 anti-democracy Supreme Court that is poised to give Republican state legislatures the unappealable last word on who won the federal elections in their state.