Consistent application of the law hasn't stopped them with Roe v Wade. It's not going to stop them anywhere else. Their motivation to maintain power, control, and the status quo takes priority over all. They'll just find some bullshit reason to rule how they like, such that rules apply for others but not themselves.
They could rule per the compact clause that the compact wasn't allowed, but reading that clause its very clearly a military/defense clause and not a voting one. Fair amount of depth there.