Implementation of Socialism and Capitalism

As you can imagine I get into numerous debates with advocates of socialism. While I think Ludwig von Mises demonstrated that socialism will always fail in his book Socialism: An Economic and Sociological Analysis the debate will continue to rage on for eternity. One thing I often bring up is the conditions experienced in socialist countries like the former Soviet Union, communist Cambodia, North Korea, etc. When I bring this up the devout socialist I'm debating is always quick to rebute my statement by claiming those countries didn't implement socialism correctly. I'm willing to conceded this point but when I make the same argument about capitalism the devout socialism will usually argue that America proves capitalism can't succeed.

Here's the thing, if you are going to use the argument that socialism hasn't succeeded because it wasn't implemented correctly you must also recognize that argument regarding capitalism. The United States isn't a capitalist country, it's a fascist country that married the state and private corporations long ago.