How did Arthur Miller use the witch trials to represent the McCarthy witch hunt?

Read lots and read carefully:

http://www.google.com/#sclient=psy&hl=en&q=arthur+miller+crucible+mccarthyism&aq=f&aqi=g4g-o1&aql=&oq=&gs_rfai=&pbx=1&fp=280187d6f0589da0