Today's Irish Times editorial (sub required) claims that "November was the worst month so far for coalition forces in Iraq, when the rate of deaths and casualties suffered by US troops became greater than during the Vietnam war".
I don't know about that. During November, the US suffered 109 military fatalities and 344 wounded (thanks to Jason for that tip). In Viet Nam, the average monthly loss was 526 killed in action (that does not include other deaths) and 1,700 wounded.
