This idea would work as follows:
A CP proposes an economic treaty with a counterpart country for example the USA.
For 1 month the citizens enjoy a 10% bonus to production in held regions.(strategy)
A country can only hold 10 treaties at any given time.
A country that holds a treaty with an other is allowed to protect its rights. They may NE any treats to regions in their partners country without borders. If they liberate a region it resets to the original country. For example Croatia attacks Kentucky USA and takes it. Serbia has a treaty they NE Croatia and free Kentucky which is now again a region of the USA not Serbia.
During the treaty the countries cannot :
1.NE each other
2. Declare war on each other.
3. Fight in any battle even in other countries with each other.
1. Signing treaties will offer economic incentives to less well endowed countries.
2. Singing treaties will offer protection to countries with good resources. So chosing your treaty partners will offer protection from would be invaders. However a formula will be in place. A country can only have say 4 top 10 countries 4 11 to 40 and then 2 40 to 74 ranked countries.
If we look into History world war 2 started because Germany invaded Poland. If they didnt as far as I can remember some countries like Austria would still be under Nazi rule. The gulf war started because Iraq invaded Kuwait which is definitely an important trade partner with the USA.