[Noble713]

In one of my recent games, I asked the Toltayans (Brotherly Partnership) to break their Trade Alliance with the Drushocka. I checked the Treaty Grid a turn or two later, and was quite suprised to find that they had done so. A little while later I asked them to support me against the Drushocka (or declare war on them, I forget now) and they did. I don't know if they were actually fighting, but the Treaty Grid said they were at war.

I think the Diplomacy works when it wants to, which unfortunately isn't often enough. The above example is one of the few where it actually has, so the underlying diplomatic capabilities are there, they just need some tweaking to make them work on a more regular basis.