Abraham Lincoln was already warning in the 1860's that big business interests were threatening to subvert and destroy the democratic traditions of the USA. It's inevitable, really, that that would happen in a $ySStem where money is the final arbiter of all important decisions, and where decisions are made in order to secure profits...and other forms of personal gain for those in charge of either making the decisions...or going along with them.

You can easily hire people to kill the ones who don't go along or to simply intimidate them into silence. You can control the primary media sources, because you own them. You can edit what people hear about and what they don't. You can shape media reporting to mould the common people's perceptions of reality.

The only real chink in that armor is the Internet, at this point...and the fact that these guys don't control the whole world. They're working on doing so, mind you, but I do not think they will succeed.