Is it really true that if the US isolated itself, the world would fall into chaos?

[James Ramirez]

According to some people online, the reason why the US has to be world cop is because if it didn't....well, the question........

 

Also according to some people, it is the only one that has the capability of doing so and Russia and China cannot be trusted.....

 

Now, if that is not true, then why doesn't Canada and the world stop them from being world cop?