America's diversity is its biggest challenge.

And what about EU with its 27 nations and different languages. Not even talking about immigration. Diversity is a challenge for all of us.

not to mention how quickly this change has happened.

America might have an issue with diversity, but compared inthe 20th century, europe as a continent has been through massive suffering.

let's not forget 30 years ago, half of the continent was divided and 40 prior to that most of it was in ruins.