I have just started playing DA after being away from GalCiv 2 for a while, so I am not sure if what I am seeing is a bug, or me not understanding things right.

Here is the situation. I declared war with the Korath because they were beating up on the Arceans. Shortly after declaring war, I research Alliances and ally with the Altarians and the Arceans. But, after many (> 20) turns at war with the Korath, neither of my allies has gone to war with them. The Arceans even made peace (although they did so before I was allied with them)!!! When I open the diplomacy screen, there is no option to ask either the Arceans or the Altarians to attack the Korath. It only lets me choose the Korx or the Terrans (the other 2 races in the game besides the Korath that I am not allied with). I looked and neither of them is allied with the Korath.

And then something really weird happened. The Altarians contact me, and they say something like "The Korath are a scourge upon this galaxy. While the time has not yet come for us to cooperate against them openly, we must work together in secret..." At this point I am thinking, "with allies like you, who needs enemies!!!"

The way I thought alliances worked is that your allies are obliged to enter wars on your side, or else break the alliance. What is the deal? The only thing I can think of is that I declared war on the Korath *before* I was allied with either the Altarians or the Arceans. Do alliances only work if you go to war after the alliance exists? It seems odd that I don't even have the option to ask them to declare war on the Korath.