He did that on purpose; that's a sleazy lawyer trick!
It seemed there were a lot of trial-lawyer debate tricks by Edwards. You could hear it in the structure of his parallel sentences and the practiced co-ordination of that structure with his hands, head, and eyes. But to me it appeared as all technique and no substance.
Although Cheney tended to data-dump on the issues, he got in about 3 or 4 of good solid easy-for-idiots-to-understand points. I think those tipped the scale clearly for Cheney in this debate.
At times, Cheney appeared a little tired and under pressure. It could have been he was trying to appear more mature than Edwards. One of the PBS commentators mentioned it also.
But it was apparent that Cheney's great contribution to the current administration and perhaps in the next one is his ability to think issues through deeply and that aura was displayed in the debates. So Cheney wins.
Hoppy