Full Idea
Grotius explored the implications of the idea that nation-states were under no obligation to help one another, but they were obliged not to harm each other.
Gist of Idea
Nations are not obliged to help one-another, but are obliged not to harm one another
Source
report of Hugo Grotius (On the Law of War and Peace [1625]) by Richard Tuck - Hobbes Ch.1
Book Reference
Tuck,Richard: 'Hobbes: a very short introduction' [OUP 2002], p.28
A Reaction
This is quite a striking disanalogy between accepted personal morality and political morality. There are signs in recent years of some recognition that other nations should not just sit and watch suffering.