====Invite/Kick/Leave Defensive League====
You need to be a Major Power or greater to use this action.
You can protect any nation of lower rank from being attacked, giving you
casus belli on anyone attacking them.
====Intervene in War====
You can use a claim, to demand a nation to secede a city or province to you, to avoid an expensive war. You need to be a Major power or Great Power to use this action.