We're a few days away from the opening of the Summer Olympics.

But a cloud of doping allegations is threatening to dampen the sunny Rio festivities. 

The World Anti-Doping Agency released a report last month alleging Russia's sport authorities covered up a widespread system of cheating doping tests at the Sochi winter games.

It's the latest in the decades-long effort to keep competition pure -- but can the Olympics ever be truly "clean?"

Donald J Polden  with the Institute of Sports Law and Ethics at Santa Clara University joins Take Two to discuss whether or not doping can ever be completely eliminated from the Olympics

To hear the full segment click the blue player above.