Aha! That's the key. You were examining aid. I didn't do that, I just looked for nations that were somewhat weaker than me and didn't have many troops. This naturally means that they tended to have more infrastructure and land since it takes
something to make nation strength...
But I didn't think to check public records of aid.
Now I've got the key. Look for trust fund brats, beat them up and take their candy.
The next question is, how hard is it to end a war? They 'expire' after seven days, but if you offer peace do the victims tend to accept or do they try to counter attack?
I haven't seen any reaction in my two test cases yet.