question: How many cases broke ideological lines than were decided by a 5-4 vote?
#1 return cases 
#2 return #1 that broke ideological lines 
#3 return #1 that were decided by a 5-4 vote 
#4 return number of  #2 
#5 return number of  #3 
#6 return the  difference of #4 and  #5