Again, I wasn’t proposing this is what happened in the Havana case. It’s not clear to me that what happened in Havana wasn’t just a panic of some sort, much like the recent drone panic. If it were some sort of attack, it raises a lot of questions about what the purpose was, why Cuba, why we haven’t seen anything like it since, why all the victims of the attack are still walking around attending meetings in Washington DC, etc.

That all said, I still don’t see why a microwave beam weapon is implausible in principle. It might not be the most practical thing ever - that’s why I compared it to polonium and ricin. But for example, using a parabolic reflector you can focus microwaves over the kind of distance between two buildings perhaps across the street from each other. If the beam only has a diameter of a few feet at the target, and only used for a short period, how is that going to be detected? You’d aim it at someone’s head visible through a window, for example, and the source of the beam could be behind a closed window with a curtain.

Btw this subthread seems to have been removed from the OP page at this point, apparently because the comment I replied to was flagged.