Just a note; the Corsairs aren't attacking Bretonia (as in BAF positions), they're attacking Mollys (as in the no1 pirates in Bretonia). They're attacking the Mollys to wipe them out and take control of the piracy in Bretonia fully, not conquer it (they can't).
So, it's not a pincer attack as some might assume; in a way it sort of removes some pressure from BAF in making the Mollys focus on stopping Corsairs.