CNN murdered it by putting people up that can't debate.
To be fair, most people your side of the Atlantic can't debate (formally that is - the only team from an American university ever to win the Worlds Debating Competition was comprised of two English ex-pats - the only nations who really do well at Worlds are Australia and England)
Talking about that, I got a 73 in my last debate last year...ouch...
It's good to know we're good; I suppose it has a lot to do with the parliamentary system (although that wouldn't explain why Canada underperforms...)