Decoding some alliance chain oddness

[arthurs towel]

So I'm looking for some clarification on an odd situation that came up last night. As the Prussian Emperor I called an Imperial Ban CB against Burgundy. Austria, my favorite war dog, naturally joins the war against their rival. Hungary, my other solid ally, can not since they are already in a war with Savoy and Burgundy against Switzerland + others. To be expected so far. No big deal as I could probably take Burgundy + Hesse (who now owns ~ 10 provinces) with just my vassals, but with Austria it should be a complete rollover.

Anyhow about 4 months later I get a CTA from Hungary, they are being attacked by Serbia in a trade war. Hungary is defender, but Serbia is allied with Austria. I accepted CTA, saved, then shut down for the night. My question is this - how does the AI determine who can't join the war? Do I get the CTA first since I am joining the side of the defender, so Austria gets locked out? Meaning if roles were reversed Austria would be able to block my entry? Or is it the Human player gets precedence?

This is obviously an edge case regarding alliances, since the attack isn't directly against me, but rather ally of my ally attacking my other ally. Any insight would be welcome.

 

[eple]

It depends whether or not it's a defensive or offensive war, I believe. If it was Hungary attacking Serbia then they would not be able to call you in, as you are already fighting on the same side as Austria in another war.

 

[PedroVargas]

Best case scenario: It's a defensive war, you are much stronger then Hungary and therefore become war leader - which let's you call in Austria. Because it's a defensive war, they even might join. Serbia dead.

If you don't become war leader, Austria might still be reluctant to join Serbia's attacker side.

Not so good: Austria already joined on the attacker side.

 

[arthurs towel]

Best case scenario: It's a defensive war, you are much stronger then Hungary and therefore become war leader - which let's you call in Austria. Because it's a defensive war, they even might join. Serbia dead.

If you don't become war leader, Austria might still be reluctant to join Serbia's attacker side.

Not so good: Austria already joined on the attacker side.

Oh I've no worries about Austria. Even if they weren't my ally in the war against Burgundy I'd be able to take them. Prussia + 6 NI's + full Quality + 5 Offensive + Emperor forcelimit bonus + 6 vassals = dead Austria if I needed. Thing is I don't want to, nor do I think I'll have to (they are my ally in another war after all, so it should prevent us from being at war with each other). Bosnia? Fly meet windshield. I'd probably take their entire force out for <1000 lost manpower. 2x33 stack + 6/5/4/1 general against 9 stack... yeah.

Main thing is for the last 15 years of game time my available manpower has been nil. A couple ov very costly consecutive wars Poland + Lithuania - Burgundy + Hesse + Spain - Poland Lithuania again while at war with Burgundy. All wins, but by the end I was spent, with 0 reserve, and only about 20k troops (over half mercs).

No I was mostly curious why (if it does) my call to arms takes precedence, figuring it has to do with this being a defensive war. No I didn't become war leader though, even though my forces are 3+ mil tech levels above Hungary, and my forces 3x size.

 

[AurochsAway]

Defensive CTAs take precedence over offensive ones. This can be annoying if an ally says they will join you in the war screen, but then an ally of the defender gets called in who has a truce with your ally, making your ally unable to join afterwards.