I suspect that a serious opponent could cause huge damage here in the States without much effort. Our daily life relies on complex systems for electricity, water, food transport and delivery, medicines.
Just interrupting the internet or phone service would make people crazy and cause chaos. Shutting down essential services that we take for granted would be much, much worse.
Anyone who remembers watching James Burke’s “Connections” would understand.
Yes power out for a few weeks
It’d be Omega Man