I question ProtoAvatar
's assumption that a thalaron weapon would even work
on the Borg. NEM established that thalaron radiation only affects organic matter. When the Romulan council was assassinated, their bodies turned to dust but their clothes and the council chamber itself remained intact.
Now, yes, the Borg do, as a rule, depend on a mix of biology and technology. But we've seen what can happen when a Borg cube is stripped of all its organic drones. As shown in Before Dishonor
, the contingency plan for such a cube is (at least potentially) to switch its nanotechnology into a more aggressive, virulent mode that "absorbs" and converts all matter it contacts. Given that precedent, I'd say that using a thalaron weapon to kill the Borg's organic half would be a suicidal move, because it would probably end up making the Borg cubes even more destructive.
I think what ProtoAvatar
is missing is that the thalaron weapon never had any serious prospect of bringing victory over the Borg. Proposing it was a desperation move. Intellectually, Picard knew he had no chance of stopping the Borg with a thalaron weapon, but he wanted to hurt
them, to get in one last parting shot before the end. It was a childish attempt to lash out in hatred and rage, not a legitimate victory strategy. That, as much as anything else, was why Geordi was against it -- because it was simply not a valid solution.