Actually I believe that Liberty is at the best place it could be.
Not getting involved.
You cannot go to Kusari's land and start "insuring" some things.
This isn't a war between two scrap countries so that "Big boss" can come from downstairs and "police" the situation. War between two houses where any involving will cause Liberty to suffer.
And noone from Liberty wants Liberty to suffer.
Refugees are actually allowed trough the Kusari space, only thing that's not allowed is to have Bretonian ships haul them from there.
As for Corsairs. They did some good things, they did some bad things. Hessians effed them up, and ETA stretched their defenses bit. But with Leeds falling down, Cambridge smells more and more like Corsair land day by day