I wonder if the author's point would hold, if biological weapons were used by the attacker. Smallpox made the first European invasion of North and South Americ

I wonder if the author's point would hold, if biological weapons were used by the attacker. Smallpox made the first European invasion of North and South America a lot easier. A few well targeted weaponized viruses with a reasonably long incubation period could greatly reduce our ability to defend ourselves. (The trick would be making sure they didn't spread beyond US borders in an increasingly globalized society)