The weak invite attack. That is a law of nature. Nations are in the state of nature with respect to each other. Talk of international law is empty verbiage without an enforcement mechanism. There is none. Or at least there is none distinct from every extant state. The same goes for diplomacy. There needs be a hard fist behind the diplomat's smiling mask. There had better be iron and the willingness to shed blood back of that persona.
Or as Herr Blut-und-Eisen himself is reported to have said, "Diplomacy unbacked by force is like music without instruments."