2 ways:
1- buy politicians, media, courts, etc.
2- use wedge issues to keep us fighting amongst ourselves — divide and conquer.
Wedge issues: immigration, abortion, gay rights, red vs blue, urban vs rural, race, college/not-college, trans, young vs old, etc.
Each time I see someone of one side of a wedge issue attack someone on the other side I wonder if they're intentionally carrying water for the billionaires, or just have been made into a sap by the billionaires, as they're doing the billionaire's work and contributing to our being fucked over.