Role reversal...The U.S. is in serious decline morally spiritually...and naturally economically. They should have listened to Solzhenitsyn in 1978 at Harvard when he warned the Americans.
Or read this: Interview with Yurii Bezmenov
Or even more basic and foundational, just read and heed God's warnings in the Bible about what happens to countries who forget the Lord, who become immoral, decadent and idolatrous.