John Stuart Mill tried to delimit a realm of government action and a private realm that was off limits to the government by claiming that the government could not interfere in purely private actions. But Bosanquet notes that there is no such thing:
"For every act of mine affects both myself and others; and it is a matter of mood and momentary urgency which aspect may be pronounced characteristic and essential" (p. 64).
The line can be drawn wherever one wants, and thus Mill provides no limit to government action at all. (For instance, Mill himself proposed forbidding those without means to marry.)
Bosanquet then offers a superior criterion for making this judgment:
"Throughout all these objections to authoritative interference we trace the peculiar prejudice that the criterion of its justifiability lies in the boundary line between self and others, rather than in the nature of what coercive authority is and is not able to do towards the promotion of good life" (The Philosophical Theory of the State, p. 66).
Of course Bosanquet's criterion does not spit out determinate answers like a computer dating algorithm. But rather than relying on some abstract notion of the "rights" of the individual, we have a criterion that demands we pay attention to the actual effects of a law in deciding whether it is a good idea. Should heroin be legalized? We should answer not by pointing to some fictitious "right" of people to take heroin, or their "right" to be free of addiction. (And notice how both sides in today's debates usually invoke rights: "I have a right to all the property I have amassed!" "The poor have a right be free from hunger!" It is a war of abstractions.) Instead, we should answer by asking the further question, "Will we have a better society if heroin is legal or illegal?" or "Will we have a better society if there is a social safety net or not?"
Granted, people will disagree about the answer to that question. And some people will make up an answer the yields the result they want. But as Oakeshott asked, "Do you want to be told that in politics there is, what certainly exists nowhere else, a mistake-proof manner of [determining] what should be done?"