Transgression

[ArtistofWarfare]

Personally, if even an ally sends an army into my lands, I them in front of their children and feed their heads to my horses. I don't put up with border offenses.

If an ally chooses to disrespect my borders I like to send "subtle" messages to him in the form of repeated, frustrating, deliberate acts of terrorism inside of his most lucrative cities.

So basically- sure, you can keep your army there...as long as I can keep blowing things up inside of your cities and sitting back with a confused "I dunno anything about it" look on my face.

I don't tolerate border offenses either. But I don't respond to them first by putting my own army out onto the battlefield. I just like to give the other faction a little sneak peak into the kind of war they'd be getting involved in if that army has any bad intentions.

If my ally chooses to attack with that army during this "phase", well a) he broke the alliance b) he started the war with an attack c) he's already been getting worn down by my assassins d) he has absolutely zero element of surprise.

p.s.- If applicable and possible, I'll also surround their naval fleets with my own fleets and park ships near their ports. So basically, yes- border offenses by my ally on my own lands are basically the precursor to total war for me.