Dan Rosenheck argues in Newsweek that comparisons between Mexico's battles with organized crime and the invasion of Iraq are erroneous, basically because the former is a war of necessity, while the latter was not.
I made a similar argument a few years ago, for similar reasons; to equate the two is to gravely undersell the needlessness and arrogance motivating the Iraq war. And it's also worth mentioning that Mexico can't pull out of Mexico the way the US can from Iraq. Calderón can remove the army from the picture, but the Mexican government is going to have to do something address the insecurity in the nation regardless of whether people are calling it a war or not.
Per my point a couple of days ago, I also think Rosenheck and other analysts make a mistake in conceding that what Mexico is living through is even a war, comparable to other interstate conflicts. (To be sure, policy-makers are the most responsible for this fallacy, since they've been discussing drug policy in primarily bellicose terms for two generations.) Lots of people are certainly being killed, but it's no more a war than Capone in Chicago was in the 1930s, than the Colombians and the Cubans in Miami were in the 1970s and '80s, both of which situations also ended the lives of many people in the United States. The dynamic at play is fundamentally different, and comparing any of the above examples to Iraq or any other invasion of a foreign nation confuses far more than it illuminates. It's apples and oranges, basketball and monopoly.
Update: Forgot to mention before that this came from the Mexico Institute. Also, I found it odd that Newsweek says that Rosenheck "was recently the Mexico City bureau chief of a newsmagazine", evidently afraid to name that magazine as The Economist.