[lxgr]

Not sure what to call a rule that immediately stops applying to any involved party as soon as one violates it, but "law" isn't a word that comes to mind.

[Sabinus]

Our usual understanding of law has an enforcement mechanism of the nation on individuals, not voluntary agreements sovereign nations enforce on each other.

[scotty79]

It's called pragmatism. It's one level above the law for practical purposes. It dictates when to apply the law in the international setting.