To what extent should the state involve itself in the life of private individuals?
Go back 100 years and the state did very little. Since then, its function has increased dramatically in most countries. Early state functions could be summarised as defence, law and order, and provision of a safety net for the indigent. Today education, transport and a degree of healthcare can be added to that. So can a plethora of other functions, some of which are designed to enforce policies rather than provide identifiable benefits. As functionality has grown, cost has become an increasing proportion of national wealth.
So where should the line be drawn? What should the state provide? To what extent should the state be able to enforce behaviours on its citizens?