Alliances and Federations is the topic of the latest Stellaris developer diary, and things are going to be much different from what you might be used to from Crusader Kings and Europa Universalis.
If you're reading this you probably like a bit of strategy, so why not check out our list of the best strategy games on PC.
Where you might have been dragged into conflict because of the decision of an ally in another Paradox strategy game, alliances in Stellaris will be more complex multilateral affairs, each member having a say in whether alliance members will be able to make a declaration of war that could affect other council members.
"In Stellaris, alliances are multilateral (they can have any number of members, not just two), and are thus more like NATO and less like the complex web of mutual agreements that existed at the outbreak of the Great War," says game director Henrik Fåhraeus in the developer diary. "This means that members of an alliance need a greater say in matters that concern the entire alliance, notable declarations of war (and some things are simply not allowed if you are an alliance member, such as guarantees of independence.)"
So you'll need the approval of other alliance members if you want to go to war, and they're less likely to greenlight a conflict if it only benefits you. So you'll either have to make interesting compromises or leave the alliance to achieve your goals.
There is another option in place, however. Alliances will have the option to form Federations, which are a compromise in themselves where total control rotates between alliance states, and the president at any given time is allowed to act with impunity. If you're willing to endure periods where you have no say, you'll be able to take advantage of being a mad dictator for a limited time, perhaps subtly affecting the needs of the other alliance members to align better with your own.
Better yet, Federations have access to a joint space navy - a fleet of ships built from the best technologies from the allied states, as chosen by - and controlled by - the president at any given time. It sounds like a system that could generate some interesting, unpredictable scenarios.
In the next developer diary we'll be getting more insight into how the game's multiplayer will work, so keep an eye out for that.