...three way multiplayer campaigns?

If so, it would be extremely hard to pull off. For example: The Rebels and the new pirate faction are fighting a space battle. Meanwhile, what's the Imperial player going to be doing? I sure wouldn't want to be a spectator in a battle that's not mine, so I wonder if this would even be possible in multiplayer.

Good question to ask at the May 25th Live Dev chat.

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It would be a sweet thing to pull off. It may not be practical for conquest mode, but it could certainly be done with a skirmish.

It could definentaly be done in a single player conquest (it's basically already there in some Conquest scenarios) but multiplayer would be the problem....

Just lock it for two players. Easy answer to the problem :) Besides, such kind of game types are not made for more then two players to face-off.

It would be easy to deal with, the third player can go and make units, he can set up his move, OR he could even have his fleet warp into the battle mid fight, what I mean by all of this, he has the choose to watch, and enjoy a good fight through cinamatic mode. OR he can build units(would be in a pause type timeway) and he can switch back and forth between them. Then if he has a fleet, he can move it to the fight, and have a choise within a 5minute timelimit to move his fleet in, if the timelimit runs out, he is forced to go in. Get what I'm saying?

Well the devs have said this:

In galatic conquest -> Still only two players.
Skirmish -> All three sides can play.

Settles that question. :)