import re
reg = r'((Opposition|Oppose):?\s*)(.*?)\n\n'
str1 = """Opposition


          California Attorneys for Criminal Justice
          Californians for Safety and Justice
          Drug Policy Alliance
          Friends Committee on Legislation of California
          Legal Services for Prisoners with Children


           Analysis Prepared  
"""

str2 = """Oppose:   None received

                                      -- END --

                                      """
match  = re.search(reg, str1, re.DOTALL)
print match.group(3)

match = re.search(reg, str2, re.DOTALL)
print match.group(3)