Why do Liberals deny the facts in a debate even if you use Liberal sources?

Because they lie so often that they believe what they say is true.

Y!A Cons much worse. Best economic president in history: Bill Clinton. But then, why bother posting a fact to a con?

My guess, based on your personality as observed on Yahoo answers, would be that you largely confuse opinions and commentary for facts.

You don't think logically, you tend to just post an opinion and then claim this proves your opinion.

Like when idiots claim "You like homos, right? So if Palestinians hate them, you must love Israel"

"Willful suspension of consciousness, the refusal to think—not blindness, but the refusal to see; not ignorance, but the refusal to know. It is the act of unfocusing their minds and inducing an inner fog to escape the responsibility of judgment—on the unstated premise that a thing will not exist if only they refuse to identify it, that A will not be A so long as you do not pronounce the verdict “It is.”"

According to the "Progressive" authors of today's liberal agenda, LYING ABOUT IT is absolutely necessary else no more than 20% of people can possibly be persuaded to support it.

Wow evidence of the impact that generations of inbreeding has on sentient thought

Most don't. Conservatives often use non-facts in debate and try and pretend they are facts. I hear often that "Fox News said" and unfortunately nothing on fox news is ever truth or accurate.

No we do not. We have the facts on our side. Cons just make up whatever they choose, Just to support their arguments. Im sorry.. These are the facts.

Liberals will always deny anything that they don`t believe in, to them the truth is hate speech.