Most of the violence in Mexico is directed at drug traffickers and those associated with them. Tourists have not been targeted. Last year, of the 111 Americans killed in Mexico, apparently only 1-2 were tourists. Most of the others were associated with the drug trade, were government officials, or were living in a border town (often Mexican-born naturalized US citizens living in Mexico). Even the State Department warnings states "There is no evidence that U.S. tourists have been targeted by criminal elements due to their citizenship." Also, over half of the American deaths occurred in Ciudad Juarez and Tijuana. There are over 1 million Americans living in Mexico and 10-20 million that visit each year. Over the past several years, you can point out the few cases of tourists killed, but if you consider the number of Americans visiting there, it is a pitifully low murder rate (i.e., a homicide rate on the order of 0.02 per 100,000 per year). Even if you consider the entire number of Americans killed in Mexico in recent years (71-111/year and declining) vs. the number living and visiting there, it is still a very low rate (1-2 homicides per 100,000). In fact, it is a rate that is much less than the homicide rate of the entire US (6.8 homicides per 100,000 per year) and far less than dangerous cities such as New Orleans (76 homicides per 100,000 per year). You can do some more searching yourself, but I'll point out a few things I found in web searches:

"The US is in fact one of the safer (not safest mind you) of countries with a homicide rate of 6.8 per 100,000. Mexico stands at 13.7 including the drug war murders. If you deduct the drug war combatants Mexico's murder rate is slightly higher than the US at 7.2 per 100,000. (Source US Department of Justice & Mexico's PJR)"

"Calderon said 'you could count on your fingers' the number of drug-related incidents that involved tourists traveling in Mexico."

The author argues that adjusting for the number of visitors and time spent in Mexico, visiting Mexico is safer than visiting many cities in the US. 

"The US government has not found a widespread increase in attacks on Americans but many crimes go unreported, admitted Charles Smith, a spokesman for the US consulate in Tijuana."

"As a new travel warning by the U.S. State Department (http://travel.state.gov) points out, the areas of concern are not the beach resorts or historical cities most Americans visit, but rather the border towns, specifically Tijuana, Nogales, Ciudad Juárez, Nuevo Laredo, Monterrey and Matamoros."

Perhaps a personal account can hold more weight. Over the past 14 years, I (Rocky Contos) have spent about 34 months down in Mexico - exploring rivers in the "drug country" of the Sierra Madre mountains - and have never encountered issues of drug violence toward me. I have dealt with petty theft and police officers that try to get some bribe by claiming infractions.  You may wonder whether a large group of tourists might be perceived differently than a solo person or small group of tourists.  Actually I think with a bigger crowd, there is less likelihood of assault - after all, assailants would be facing potentially more resistance.  

On trips like the Mulatos-Aros, we are not going to linger in the border towns where the violence is occurring. We'll basically get the tourist cards (where we will be pretty safe due to police presence), and drive through. We are avoiding the most dangerous border cities - Ciudad Juárez, Tijuana, Nogales, Nuevo Laredo, Matamoros - where the majority of the violence occurs. If you are concerned about the actual border, then you can look into flying directly into a Mexican city (such as Hermosillo for the Mulatos-Aros trip, or Chihuahua for the Conchos trip).  

On trips in Chiapas such as the Usumacinta, we are also along a border area but there is not nearly the level of violence as in the US border regions. However, everyone should note that nearly anywhere in Latin America, there is a chance of armed robbery. If this happens to occur during a SierraRios LLC expedition, we will do all we can to protect our participants and ourselves. However, SierraRios LLC is not responsible for any personal injury/damage/loss that may occur during the outing. We highly recommend that you (a) minimize the valuables you bring on the river, and (b) only take small amounts of cash, and (c) obtain a travel insurance policy that will cover losses.

There is a danger to traveling in any foreign area. The increased violence in Mexico associated with the drug war is not generally affecting tourists. It is about as safe for tourists to visit Mexico now as it was 5, 10, or 20 years ago. It is extremely unlikely that we will be assaulted during one of our expeditions. If we are assaulted, it is likely to be only to obtain our possessions at hand. Everyone will have to make their own decision whether they wish to take the risk to travel in a foreign country like Mexico. However, for the tourist, just realize that it is about as safe as it has always been, and similar to other parts of Latin America.