Perhaps you should...
...also compare the number of Vietcong versus the number of Iraq insurgements. I suspect that you'd find on a per casualty basis, the latter have been far more effective and deadly.
But you're missing the point...the point is the number of casualties in Iraq are not too terrible different than the number of casualties in the early days of Vietnam. The real question is how many casualties will the American people tolerate in Iraq before the anti-war moveement overwhelms the country? Remember that now most Americans think Iraq was a terrific mistake.