After noticing differences in the environment around certain areas in the US, the government sent government researchers to investigate for hopes of applying the same techniques elsewhere for profit.
Arriving unannounced, the investigator catches the society red-handed and reports back to tell the government that the seizing of the property, weapons, farming equipment, ect. could make a lot of profit AND be legal due to the prohibition of guns in unauthorized hands.
After Having their land seized and their community dissolved, the family were left to the middle of nowhere with nothing to survive but a few bucks and each other for the winter.
The government ended up killing off too many animals throughout the winter. The fields grew barren due to no fertilization, and the exact opposite of the first problem started.
The western hemisphere soon grew to be uninhabitable due to no plant or animal life because of overhunting and improper farming methods.