Possible Clues:

• Crank turning, in fact, engrosses one
• Soccer body in charge, harbouring national extremist
• One who is excessively zealous
• Narrow-minded enthusiast
• One is motivated by irrational enthusiasm
• Be moderate one can't, if a person like this
• A zealot - in fact, a loony
• Crazy American in fact is a zealot
• True believer
• Wild and crazy guy