> Why does the state have a role to play in a transaction between two consenting adults? The only sensible argument would be that the state has a role only insofar as consent is in question
Because that is fundamentally the purpose of government. Roughly, to intrude in the decisions of individuals in order to generate a safer and more prosperous life for everyone in general. A civilization is more than a collection of individuals.
Consent can be coerced, scammed, misinterpreted, hard to prove afterwards, etc. And individual actions have consequences beyond the individual because of human traits like envy and greed. So, government attempts (should attempt) to take all these factors and many more into consideration while creating regulation and enforcement structures that work around those problems.
Because that is fundamentally the purpose of government. Roughly, to intrude in the decisions of individuals in order to generate a safer and more prosperous life for everyone in general. A civilization is more than a collection of individuals.
Consent can be coerced, scammed, misinterpreted, hard to prove afterwards, etc. And individual actions have consequences beyond the individual because of human traits like envy and greed. So, government attempts (should attempt) to take all these factors and many more into consideration while creating regulation and enforcement structures that work around those problems.