This week Senate Democrats once again asked the IRS to crack down on conservative groups including Americans for Prosperity, funded by the billionaire industrialists Charles and David Koch.
Democrats want to silence the opposition.
So how big of a threat are the Koch Brothers?
Over the past twenty five years, from 1989 to 2014, Koch Industries has donated $18,083,948 in political contributions to Republicans. While that seems like a large sum, it only ranks them as number 59 on the list of top all-time political donors – behind 18 different unions.