That's the problem with British politics. We're all in the business of fighting each other. When someone comes along with first-hand knowledge of the topic in hand it just confuses everyone.
Suppose a fox turned up at the debate on hunting, and said that, yes, it was true, he and his friends really did enjoy the excitement of the hunt. It wouldn't change anyone's mind at all!
The speaker yesterday was Shanaz Rashid, an Iraqi exile who has lived in Britain for 20 years. Her performance was compelling, alarming, somehow keeping just on the leeside of hysteria.
Her voice swooped and dived, rising almost to a shriek before falling back again, as the tears were choked away.
At times she looked as if she was about to spontaneously combust right there on the podium.
The liberation of Iraq, she said, was a dream she had had all her life. When, after Saddam had been defeated, she landed at Baghdad airport, she had kissed the ground, and "wept for my freedom! Freedom that you take for granted!"
She described how her relatives had been tortured and murdered by Saddam, and how the west had ignored their plight.
"Those people who say that the policy of containment was working deceive not only other people, but also themselves. The political will wasn't there."
In the second world war, the Americans had come to our aid to destroy the evil forces of fascism. "Surely there is no dis honour in helping me to get my freedom?" she said.
"You may feel you can attack your leader, but it is Mr Blair who has stood up to Saddam and has freed my people!"
By this time her face, viewed on the two giant screens, had crumpled with a mixture of rage, frustration and relief.
"Yes, there have been difficulties, yes there have been mistakes, perhaps many mistakes.
"No, you didn't find weapons of mass destruction. But for the great majority of Iraqis, WMD were never an issue. We never understood the argument about them.
"All we wanted was to be free! Free! FREE!" she cried, her voice peaking dangerously as TV sound engineers ripped off their earphones and stuffed tissues up their bleeding noses. "Please, please, do not desert us in our hour of need!"
To a conference that was in the middle of a convoluted discussion about whether British troops should leave when the Iraqi government asked them, or go somewhat earlier, this was an alarming dose of first-hand feeling.
You could almost see the anti-war people muttering to themselves: "Is she genuine? Is she really an Iraqi? Where did they find her? How did she get called? Was she prepped by Alan Milburn? Maybe she's one of those actresses they get to liven up the morning chat shows by pretending to have a husband who sleeps with goats."
Nobody knew how to cope. As Ms Rashid fled from the stage, all passion spent, she was followed by a Marian Grimes from Edinburgh, whose voice was as low and mumbly as Ms Rashid's was high-pitched and furious.
"I'm finding it very difficult to follow that," she said, but she soon found a way: she simply ignored it, and didn't address a single point that Ms Rashid had made. Nor did any of the troops-out-now people. They simply pretended she hadn't been there.
But none of it mattered. The vote had been stitched up well in advance, and the Saviour Of Iraq was never in danger of losing.
