RN vs. LPN the war continues

I'm the DNS of a small skilled facility. The nurse manager was hired long before I started. She is an LPN. I have no issues with LPNs in general, but given the choice, the acuity of the residents, and the CMS 5 star rating system which gives more stars to facilities with RNs, I would rather have as many RNs as possible. We have a newly created position. We are a union building and have to post every position. I have 2 people interested. One is a brand new LPN and the other is an experienced RN. The nurse manager doesn't like the RN and tries to find fault with everything she does. She loves the LPN (who has worked less than 10 shifts for us). She told me that she has decided to give the job to the LPN because she likes her. I told her I would rather have an RN for a variety of reasons. So now she's going around to the other staff and telling them she is 'over her' because I have a bad attitude about LPNs. I am at the end of my rope with this woman. She decides who she likes personally and who she doesn't and her personal opinions get in the way of everyone's work. The RN is not perfect (hmmm are you? am I?) but she has experience. Any ideas out there. I know it's a rambling post and no one can make this call but me, but are any of you going through anything similar?