Two things:

1. Many people don't start from a premise of: "Let's find out what The Law requires of us and we'll proceed accordingly, out of a sense of duty, loyalty, and obedience."

Instead, to a first approximation, their starting point is: "I don't give a [hoot] about The Law except pragmatically — I want to do X, so I want to know: (i) under The Law, what pain could others inflict on me if I were in fact to do X, and (ii) by what means could I prevent, or at least mitigate, such an outcome?"

2. Weather forecasting is the best analogy I've come up with to describe legal analysis: You have to make a best guess about how various "energy sources" — litigants; legislatures; courts; armed camps — will interact at a given place and time.