[Vagrant0]

By now you've noticed that often in the space stage you have one empire attacking another empire despite both of them being allies. Once this has started happening you pretty much have to decide which ally you want to keep and which ally you want to get rid of, however it can be prevented to some extent with careful planning.

First off, this plan makes use of the behavior of your allies expansion methods and the positions of stars. Allies typically do not travel more than the distance of the second engine between stars when choosing new planets. If the planets between their own and any open planets are already claimed by you, another empire, or a sentient race, they will not expand in that direction. Meaning that they key to ensuring that a warrior or religious empire doesn't start cauing problems lies in your ability to contain their expansion to parts other allies are not in by just dropping t0 colonies in those systems. The sooner you can act on this, the less work you'll have to do later as allies start coming close to eachother. If you get lucky with spice, and can find cheap colonies for sale with one of your allies, you can effectily sorround a warlike empire with a buffer space of your own colonies.

The problem is that in some parts, typically closer to the center, there is more height displacement between systems, so you may have to claim more systems in that area to block expansion. If you do notice one empire branching across, you should immediately try to make a trade route with that system and make plans to buy it before any more expansion happens.

This method can also be used in some of the "choke points" which connect your neighborhood to the rest of the galaxy to keep your allies from expanding too far away from their home, and thus running into other empires. This is slightly easier since these spots tend to require passing through 1 or 2 syetems where it thins out in order to get to any other part. So if you place colonies on those two systems and any other systems which are fairly close, you can create a barrier that your allies will not cross. This means that you can keep one part of the galaxy, around your home planet filled with only those empires who like you unconditionally, while in another part keeping a warrior empire (for cheap weapons and stronger ally ships) alive and contained.

This applies to any races you decide to raise up as well, if you keep them contained, they won't cause problems with others. If you keep them happy, they won't go demanding tribute.

As far as getting rid of those problem empires go, once they start being a problem, paying off allies to attack them can usually make your job easier. You can either help that ally claim that system, or use them as a distraction while you claim it yourself. Once the problem starts you usually have to step in or end up losing both allies. However if you capture most of the aggressive empires systems, and recreate that buffer area, that empire will only be attacking you, and eventually start asking for peace once you've knocked them down to 2-3 colonies.