People with BPD aren't great with reality perception
And kids are just learning skills to figure out what's real, what's not, so they tend to be easily persuaded (especially by emotional reasoning). They can be easily swept up in the distortions, especially if you (with good intentions) tried to keep them out of the middle, leaving the facts unchallenged.
In addition to Stolen's excellent recommendation about Childress's work, there is also Warshak's Divorce Poison, which offers a lot of tips on how to counter the alienation in effective ways, depending on what BPD mom is like and how she alienates them. You can pick and choose the examples that best fit your situation and use the tips, applying them in situations with your girls.
Glad you're here
LnL
