. Now add in the possibility of disease outbreak, if "they" have come up with something that can go a month before any syumptoms, and is air-spreadable. Look what a dozen wussy letters in the mail did, now think what an actual large state sponsored coordinated attack would be like.
I would expect that to happen first, anyway, just by default, it makes strategic and tactical sense. the tradeoff in prewarning is worth it, if the lead time is enough, because no 'blame" can be assigned to a bioattack readily.
If you think like an attacker it's too scary, because it's sorta easy to pull off. Being the attacker as opposed to the defender you have so few obstaclers to overcome. You don't have to sweat the intel because you are the planner of the important intel. You don't have to guess or analyse the time factor. You don't have to develop countermeasures which are always more costly and difficult. On and on. The aggressive attack posture per se is unbalanced, but that doesn't mean it can't be hard felt if it hits.
Back to nukes, exactly what flavor nukes is russky land putting on their topols? Maybe that's part of the plan, use massive neutron bombs so that the resources would be available in a year after the first strike. If they hit us first with bios, especially blended and altered bios that are antibiotic resistant, then with nukes conventional for the military targets and neutron for the cities, that would be about it I would say, not a whole lotta healthy folks left over.
Sure it can. With the sort of lead times you're thinking of, it'll be spread globally. All you have to do to see who did it is to look around and see who's not sick. (They would have to innoculate themselves before deploying something like that. And BTW, that sort of massive innoculation program would itself be pretty difficult to hide or disguise.)