I call this the "Alice in chains" class of cryptographic problems, where one or both communicators are under severe social and political repression, to the point that even sending messages can be dangerous or impossible even if the contents themselves are secure.
They're difficult to address because the particulars vary so broadly from case to case, and the challenges are more political and infrastructural than strictly technological or mathematical. I think one of the best things we can do to address these problems is building a resilient, low-cost, general purpose data network that can't be easily cut off at government or corporate chokepoints. Mesh networks are a big part of the puzzle.