Our economy is so incredibly complicated that it could easily breakdown for brief periods. A breakdown in the supply of opiates alone might ignite that burning and thereby create problems for the supply of all other goods and services.
That would result in martial law to fill the void and to keep the trains and trucks and planes running.
I don't think any foreign enemy would even think of getting involved until the dust settles.
There is a lot our enemies can do covertly to accelerate our demise. After all, look what the foreign and domestic leftists working in concert have accomplished in the past 80 years. We wouldn’t be having this discussion without all the foreign intervention.