I had to look it up, but “cabin(ed)” means “confine(d) within narrow bounds”
So what I think he means (in his highfalutin way) is that the state legislatures set narrow bounds within which the electors (for the Electoral College) were supposed to be elected. But several states went outside of these bounds.
Lawyers!
Nice try ... but I think it’s a typo and the lawyer who wrote it should be embarrassed.