If it's about US, the answer is: In the nation’s history, presidents have used military force t<span>o have supreme</span>.
Government Debt.
Corruption.
Extreme weather.
Lack of control in local food.
Lack of access to education.
Mental illness - lack of proper psychiatric care.
World hunger.
Epidemic diseases.
I know that manifest destiny was the mindset of Americans that they were destined to stretch from coast to coast.
The Louisiana purchase was during that time. Napoleon didn't have the troops to keep Louisiana so he sold it to us for cheap.