Diplomacy is balanced on a very fine thread. One movement or word and then it will fall and shatter. Diplomacy is sensitive work and can affect the tribe’s next moves. It is a position that should not be given out freely. To get diplomacy perfect is like shooting a bullet with a smaller bullet, blind folded, whilst riding a horse. It's almost impossible.
It is said that all wars are caused by bad diplomacy. Diplomacy should not be used as a shield by any means. However, in some cases tribes do use it as a shield for a short interval; but while diplomacy is defending you then you need to build up your defences. Diplomacy should craft a double-edged sword and should be used to its full advantage. When you are not at literal war then diplomacy is at war. In times of peace, diplomacy should craftily be positioning itself ready for the next encounter. By positioning your pieces correctly then you can survive and thrive. Diplomats (or leaders, in cases where there are no diplomats) need to identify tribes, laying battle plans. And then, prepare for the inevitable attacks that will strike your tribe. This happens to all tribes and only a small minority keep going.
As a diplomat you need to be able to sell water to a fish, air to a human, and oil to Saudi Arabians. Diplomats need to skilfully lure their targets into the trap and then snap it shut. A diplomat's duties are not limited to just making allies. Their duties also involve monitoring tribes and communicating to the tribe's allies.
Most players believe that lots of NAPs and alliances is a good thing. This is totally false. Too many NAPs or alliances won't allow space for your tribe to breathe and spread out. If you have lots of alliances and then want to noble a new village. Instead of seeing noble targets, you just see a sea of blue. You can't noble anything, because they're all allies. There is no way your tribe will grow, and eventually another, larger tribe will come along and eat you for lunch because you haven't been able to expand.
Furthermore, tribes should open up a Diplomacy section of the forum. There, you can talk about who you’re getting into bed with, and who you intend to stab in the back.
Also, before we leave the subject of diplomacy, just a small mention of NAPs is necessary. Some will refer to NAP as not meaning 'Non-Aggression Pact,' but rather 'Noble All Players.' This is pretty much what you should think of NAPs. If alliances are castles, meticulously built and sometimes unconquerable, NAPs are sand castles, washed away with the tide. If you don't need a NAP, ignore it. It will give you at least some protection while the other tribe tries to figure out why you're attacking them