Outlaw 828 wrote:

If you attack without declaring war you surprise attack. With eachsurprise attack your popularity drops 25%, do this 4 times and the AIwill declare war as you will have a very low popularity.
If youdeclare war and attack straight after you won't get this highpenalty. However with each nation that you attack your popularitywill drop about 5%.

freezy wrote:

K.Rokossovski wrote:

I even doubt if we're understanding this correctly. I have always noticed a big popularity hit when starting surprise wars.

I was present when we deliberately patched out the penalty for surprise attacks in 2020, I discussed this topic myself with the responsible Dev back then. That's also why the wiki article about popularity does not list this as factor. So unless anything changed since then surprise attacks should be no different than declaring war.
I just tested it myself in a fresh game. I was at peace with nation A and B. Surprise attacking nation A decreased the popularity from 71% to 21%. Declaring war on nation B decreased popularity from 69% to 20%. So the effect of both was basically the same (with some rounding inaccuracies). But feel free to test this yourself.

Also this explanation from DxC might apply as well:

DxC wrote:

The thing is, declaring a trade embargo will erode your popularity with that country and countries that see it as popular. The more popular that country becomes the more the embargo will damage your global popularity. Since your popularity has already been damage by using the embargo going from embargo to war isn't going to look as severe as peace to war.
To figure it out it seem like you would need to start two private maps where in one you do the embargo on day x and declare on day y and in the other you just declare on day y. Track your popularity in both maps from day 0 to day y + 5ish.

freezy wrote:

Indeed the Wiki does not specify exact numbers for the existing factors. Some obviously have bigger effects than others. But I don't know them by heart as well so I cannot tell you. Also due to the weirdness of the calculation. These actions do not have defined percentage points, so there is nothing like "doing XY subtracts 25% popularity". The percentage is actually calculated by some formula that weighs previous positive interactions with previous negative interactions, meaning that you get diminishing returns when you have alot of positive or alot of negative actions. Thus the percentage changes are alot bigger at the beginning when there were not many actions yet. So the effect of these actions depends also on how much was already interacted with the country and how much positively and how much negatively. I think it was a deliberate decision to not lay out all of this in the Wiki cos its just a headache to explain, sorry. Instead we opted to just give a general guidance which actions are good and which are bad. If some players wanna figure out actual values they sadly have to test themselves.

With my posts in this thread I was only commenting about the alleged surprise attack factor and others which are not present in the game anymore, thus also not listed in the wiki. I actually quickly edited the wiki to make it more clear that war declaration and surprise attack results are the same.

Outlaw 828 wrote:

believe this is not the case now, getting confirmation

Outlaw 828 wrote:

has not changed

Carking the 6th wrote:

freezy wrote:

...

Took me a while, but found the thread. It’s called “Add 'delay' option to declaring war“ and contains the above posts.