Nearly 60 years ago, Eric Hoffer, a former longshoreman, wrote a little book about mass movements, entitled THE TRUE BELIEVER.
As you can see, it's still in print, as are other of his works.
The book opens like this:
"All mass movements generate in their adherents a readiness to die and a proclivity for united action; all of them, irrespective of the doctrine they preach and the program they project, breed fanaticism, enthusiasm, fervent hope, hatred and intolerance; all of them are capable of releasing a powerful flow of activity in certain departments of life; all of them demand blind faith and single-hearted allegiance."
Certainly, he could be talking about radical Islam. Could he also be talking about the Tea Party?
Re-reading him after decades, I am amazed at how fresh and contemporary he seems.