As to war or it's justification, etc. , it's clear to me personally that modern nations have been struggling for material resources and power and will resort to subterfuge and open war to achieve objectives...
Nations stockpile vast weapons, tax their citizens unmercifully to maintain and develope weapons and art the same time "talk" peace ...
Politicians, large corporations dedicated to large government contracts and oil companies have a vested interest in keeping things "hot" or at least "warm" when it comes to war...
At the same time international law as an institution has become stronger and world opinion and alliances have developed that can mitigate against war.
The Revelation of Baha'u'llah proposed over a hundred years counselled the world rulers and governments to build foundations for a world government and a world court. We're beginning to see the importance of this but it's taken a long time and much is left to be done to accomplish world peace and justice.
Baha'is are non-partisan and are loyal to duly constituted governments ... We request non-combatant roles if drafted.
"Jihad" has been abrogated by Baha'u'llah. It's still too easy for governments to justify war as a policy self interest and claims of being defensive through preemptive strikes, so what we need is stronger international law and a world government.
"God's purpose in sending His Prophets unto men is twofold.
The first is to liberate the children of men from the darkness of ignorance, and guide them to the light of true understanding.
The second is to ensure the peace and tranquillity of mankind, and provide all the means by which they can be established.
("Gleanings from the Writings of Baha'u'llah", pp. 79-80)
Source:
http://bahai-library.com/compilations/peace.html