Offensive Call To Arms is a one way street

[Restless Native]

Are you sure?

There are plenty of times I can't call my ally because of Distant War only to be called into a Distant War by them.

I think distant war malus is based on distance to the target. Not distance between the allies. So the above scenario makes sense. What’s more, it only counts the target and not their allies. So I think once the allies join your enemy, if they are closer than the target to your ally you can call them in afterwards.

 

[Cookiepie]

Are you sure?

There are plenty of times I can't call my ally because of Distant War only to be called into a Distant War by them.

Yes, as @Restless Native states it's based on the distance for them to the target not between you and your ally.

 

[Brynjar]

I was surprised to see that a thread with this title was about the AI getting all the offensive benefits from alliances, and not the player.

I have always found alliances with the AI too easy to abuse for my own gains, even without abusing the friendly attitude. Whether it is by not giving them promised land, not accepting CTAs, making sure their offensive war target isn't a viable target for me, signing a seperate peace deal early or simply joining a war and not doing anything since I am not in any danger myself. The downsides of not doing what your allies wants are generally too small compared to the cost of fighting for them.