This is a great example of how when things start to go wrong, they can cascade and go very wrong. Everything was dandy, and then two things happened.
First, I decided to declare war on an empire that had rebelled against an empire I was in a joint war with (with an ally who was doing absolutely no fighting whatsoever… dude just sat up there and didn’t engage, and it was his idea), so that I could reach the rest of the enemy systems. This empire was pretty tough, but I could have handled it, even with the other war happening as I had six fleets… without the second thing that went wrong. The second thing that went wrong was that I defeated a leviathan that was controlled by the aquatics(?) with which I was at war in the south. Great, right? Except, doing that came with a random event chain which I unwisely chose to pursue. It spawned another one in my home system. No big deal, right? It destroyed the starbase and just sat there, so I figured after the war I’d just go and clear it out. Except, surprise! It’s apparently not hostile to anyone else, so the neighboring empire, with which I was NOT at war, was able to walk into my home system and somehow colonize my occupied and defended homeworld (that has to be a bug?). So, biggest production machine world GONE, without a fight, in a strategic location (choke point) during multiple wars. Without the production infrastructure for my fleets on multiple fronts and the ability to move what I had, what was a mighty war machine became a massive energy deficit. That’s GG. First loss that has felt unfair (due to the AI just taking my homeworld outside of the game mechanics and that causing all sorts of cascading problems in the campaign), but life’s not fair, you play the hand you’re dealt and if you lose you play another one until you don’t. That’s what Ironman mode is for, in games. It repeatedly teaches you the important lesson that there are no do-overs, and to always tread carefully, even during the best of times, and if you fall you waste as little time as possible getting back up. ^^