I'm not really talking about
overriding sanctions; just an absence of trade/treaty relations between two countries. You can't have an iterated prisoner's dilemma on an international level without an extradition treaty. (Well, you
can, using the sort of arbitrary state-to-state gifts that international diplomatic incidents are resolved by, but that doesn't scale.)
> already has it that a contract does not have to written down to exist so if you're pretty sure things are going to go well - say mowing the lawn, you can go ahead and just enter the contract with nothing written down
Yeah, but there's a reason people do write contracts down rather than... not doing that, when they want to actually have them be enforced in the breach.
Personally, I don't even really want smart contracts to "do" anything on their own; all they would need to be useful is to be predicates—executable code running on a distributed computer that automatically detects a breach of contract, so that legal measures can be taken. That, by itself, is much more useful than a regular two-party written contract that devolves into "burn down their office to get out of the contract", or the regular three-party (you, them, a lawyer) written contract that costs $500/hr to facilitate.