Just another food fight over Iraq?

One of Passport‘s most enterprising readers writes in with a smart comment on yesterday’s post on the significance of the drop in U.S. casualties during July 2007:

[I]t does look like there’s a seasonality to the fatalities. And it doesn’t look like the 2007 seasonal drop, at least thus far, is among the greatest percentage decreases in fatalities. The one thing that this does not control for, of course, is the number of troops. It would be much more telling to look at fatality rates.

Looking at fatality rates would probably make July 2007 look slightly better, since there are now more U.S. troops in Iraq. Here’s the graph our reader made based on figures from Iraq Coalition Casualties. The Y-axis shows the number of fatalities, and the X-axis shows the month in question. Each year is represented by a line of a different color.

For Mark Mazzetti of the New York Times, efforts to understand what the July data really means are just another fight between war supporters and critics. Is he right? Should we in the media just throw up our hands and effectively say that we can’t referee this debate?