You know, I used to have an explanation for that issue of division. But I've since forgotten, so I'd have to remind myself before posting a coherent response. Maybe I will at some point - there's a book I should reference, but I would have to go find it.
What I have so far (It's late, this might not make sense): Cynics say that politics have seeped into the Court, so the divisiveness is a reflection of the political climate. I'd like to think the answer is more complicated than that. I believe part of the issue is that a fledgling Court cannot afford to be divided if it is to survive, whereas a well-established Supreme Court can. An empowered Court has more freedom to influence the government, and it has done so when given the chance.
I'd be interested to know which unanimous landmark decisions you're referring to, though, which might jog my memory further. Quite a few of them weren't unanimous.
