I've never understood the difficulty people have with always being at war, unless of course they spend all of their time attacking other races. I am rarely at war, and my wars are usually short, even now that I am playing at higher difficulty levels. I do this by making sure that as soon as I am finished with the initial expansion phase, if not sooner, I am setting up as many trade routes with as many races as possible. The AI seems to not like the loss of income that comes from going to war with you, to the point where I literally have to be blatantly obvious about the fact that I am about to swarm over every colony in their empire before they start getting even remotely hostile, other than the initial blustering upon first encounter.