The Flat Tax Through The Decades By editor • Oct 25, 2011 TweetShareGoogle+Email Last-minute income tax filer Jen Makowski works on her taxes at the main post office, April 15, 2004, in Chicago. Proponents of the flat tax argue it would make it easier for Americans to file their taxes. Tim Boyle / Getty Images Copyright 2018 NPR. To see more, visit http://www.npr.org/. TweetShareGoogle+EmailView the discussion thread.