Issue #17 of the broadsheet newspaper publication of the Platypus Affiliated Society in Chicago, New York City, Boston, Canada and Germany. November 2009, the 2nd anniversary of the initial publication The Platypus Review, is marked by a special issue on "The Decline of the Left in the 20th Century: Toward a Theory of Historical Regression." On April 18, 2009, the Platypus Affiliated Society conducted the following panel discussion at the Left Forum conference at Pace University in New York City. The panel was organized around four significant moments in the progressive diremption of theory and practice over the course of the 20th century: 2001 (Spencer Leonard), 1968 (Atiya Khan), 1933 (Richard Rubin), and 1917 (Chris Cutrone). The following is an edited transcript of the introduction to the panel by Benjamin Blumberg, the panelists' prepared statements, and the Q&A session that followed. The Platypus Review encourages interested readers to view the complete video recording of the event at http://www.archive.org/details/PlatypusDialecticsofDefeatLeftForum2009NYC041809