You can consider it to be Isolated. The doctrine was about preventing anyone from Europe from participating in political activities in the new land, and it was proclaimed that any European force that tried to control or colonize countries in the new land would be considered to be unfriendly to the US and the US would help the countries under attack.
Because why not lol sike I’ll help later
The answer is the annular eclipse
The money that got printed off and all of the other money lost value