I was surprised to discover that Brady v. Maryland was decided as recently as 1963. Not knowing enough about the context in which it was decided, I am having trouble understanding exactly what changed as a result of the decision.
Brady only addresses the disclosure of exculpatory evidence, and specifically in the context of sentencing rather than determination of guilt. (The case was remanded for resentencing consistent with the decision, but the conviction was affirmed.) I have not been able to find out what the rule was in the U.S. prior to Brady. Pre-Brady, was there any duty to disclose exculpatory evidence? Is Brady establishing this duty for the first time, or is Brady's contribution to extend this duty to apply to evidence that might only affect sentencing? Or it it significant for some other reason? If there was a Pre-Brady duty to disclose exculpatory evidence, when was it established?
I have read the original decision but I find it hard to interpret, so here I am.
I imagine that the rules about disclosure of inculpatory evidence must be much older and much stricter. Is this so? What are the major landmarks on this topic?