Ok here was the scenario. I never pulled this off because I stopped the game after a new update.
I'm the Terrans and the biggest Empire on the Block. The number 2 guy is the Krynn. Now, I don't like a large Jihadist Empire on my border so I want to knock them down a peg or two. But they have allies. Torians, Iconians, and Altarians. The Iconians are nothing so I'm not concerned with them. But the Torians and Altarians are my allies too. The Krynn and I well its a bit of a cold war.
Now if I'm the aggressor and declare war on the Krynn then their allies including the 2 on my side would probably gang up on me to defend Krynn. But if Krynn declared war on me then they are the aggressor and Torians and Altarians would defend me.
Confused yet? Ok so here is my plan. I declare war on the Iconians who are only allied with Krynn. The Krynn then move in to attack me and since they declared war this forces the Torians and Altarians to declare war on Krynn.
I'm pretty sure this is how World War I turned into a big mess. You think it would have worked?