[Maceman]

My own personal rule is that I only argue with liberals if there is a third-party "moderate" listening to the exchange, who may be enlightened by watching the liberal morph into a wild-eyed emotional lunatic when confronted with a rational argument (or pointed question).

[CGVet58]

... and that, good sir, is a most excellent observation; we don't "argue" with our invective-laced counterparts to sway them, but to allow the non-committed and nearby witness to see the extremisms from a member of the fascist left.

[Logophile]

My own personal rule is that I only argue with liberals if there is a third-party "moderate" listening to the exchange, who may be enlightened by watching the liberal morph into a wild-eyed emotional lunatic when confronted with a rational argument (or pointed question).

An excellent rule. You probably won't convert your opponent in the debate, but you might convert the bystanders who hear the exchange.