any way to cause a war

[Twotribes]

other then waiting for events to unfold randomly?

[EwaldvonKleist]

1) Always collect maximum Tensions with events.
2) Have Spionage om so you get agent caught events.
3AFAIk having colonies in the same region as other nation raises tension event chances.
4) AFAIK having many activitie ships during high tensions can escalate things.
5) Pray to RNGesus and weekly sacrifice a set of dices to them.

[varsovie]

Short answer no.

You can help the RNG by choosing the rigth option in event

You are not "God" or head of state in this game, but some sort of Lord of Admiralty/Minister of Sea/Ship or Chief the Navy. So it makes sense that you do not have the authority to declare war, but enough power to inflex inter/intra governmental relations.

[NimrodSam]

You can guarantee it by editing the .BCS file in either of two ways:

-Add the war. Easy to screw this up; if you're going to use this method, first look at an older save file that included a war.
-Easier: Raise that country's tension to 12? >12? (I forget); they will go to war with you the next month? within a month or two? (I forget that too).