What about increased bilateral relationships which includes trade, repatriation agreement and permission. The later also includes releasing of individuals who are treats to another country. I heard some countries don't have such bilateral agreement and so to have certain peaceful resolution is difficult but if such agreement can be entered then individuals or groups of people who want to ferment trouble or war can be released to home countries or the other countries for questioning and subsequent resolution. However, it is difficult to have a war free world.