Rather than a public system where all Americans have health insurance in exchange for paying higher taxes, health insurance is offered to Americans through private companies. A sociologist observes that this private system seems locked in place because insurance companies fund lobbyists who successfully oppose efforts to create a public system. Which of the following concEpts describes the development of the healthcare system in the U. S.?

1. A social movement
2. Life course
3. Critical mass
4. Path dependency