More than a year after the deadliest single attack in Mexico’s recent history, the Zetas find themselves under heavy government and internal pressure, yet public security has not markedly improved in Monterrey.

Fifty-two people died on August 25, 2011, when a handful of Zetas sprayed gasoline around and then set fire to Monterrey’s Casino Royale. It marked one of the darkest episodes in Mexico’s recent history, with media attention from the around the world. None of the dozens killed in the attack were thought to have been associated with organized crime, which led many, including President Calderon, to label the incident a terrorist attack.

The Zetas had been deemed the top priority by the Mexican government (as well as by the US) earlier that summer, and the outrage generated by the attack only increased the attention on the gang. And in some ways, this effort has borne fruit: at least 18 of the Zetas involved in the attack have been arrested in the year since the fire, including the alleged intellectual author of the attack. Furthermore the assault on the Zetas has weakened their position in Monterrey. The group has also come under fire in other strongholds such as Veracruz and Nuevo Laredo.

Such is the strain on the Zetas that the leadership appears to be in dispute; Miguel Angel Treviño, typically described in recent years as the second-in-command, has reportedly been trying to wrest the control of the organization away from his partner, Heriberto Lazcano. The fight for control of the Zetas has led to an outbreak of violence in states like San Luis Potosi, and could radically reshape of the scope of the organization.

In some ways, the assault on the Zetas represents the essence of a dissuasive response from the government: deemed the most dangerous of all of the gangs, and the perpetrators of some of the most sensational acts of violence, the government has concentrated its resources on the group, and delivered a series of heavy blows. The authors of the crime that principally earned the government’s attention have mostly been arrested or killed, and the overall pressure has been sufficient to put the organizational integrity of the Zetas in doubt.

Nonetheless, in terms of public security, the impact of this response has been decidedly mixed, if not negative. As the Zetas have grown weaker in many of the states they dominate, the violence has not diminished significantly in many of these, not least Nuevo Leon and Monterrey.

According to Mexico’s National Public Security System, there was an average of 175 murders in 2011 prior to the attack on Casino Royale. In the eight months following, which coincided with the crackdown on the Zetas, the number dropped to 155. This marks an improvement, though not a dramatic one. In other Zeta-controlled regions bordering Nuevo Leon, there was no decline in violence. In Tamaulipas, the monthly murder count has moved up from 71 up to 75 over the same period, while in Coahuila, the tally increased from 50 to 58.5.

In short, a redoubled effort to rattle the Zetas’ network has led to some visible successes, but there has been nothing like a peace dividend. For analysts who argue for a strategy more focused on dissuading the criminals, the case of the Zetas following the Casino Royale raises an important question: why hasn’t it worked?

One response may be that it has not been forceful or comprehensive enough, both in terms of the arrests and government efforts to communicate its plans. Regarding the former point, while a number of high-ranking Zetas have been arrested (including the group’s alleged number three, Carlos Oliva Castillo), the two supreme leaders, Treviño and Lazcano, remain at large. Furthermore, the government has rarely explained its focus on the Zetas, and indeed the prioritization of the gang months before the Casino Royale attack was only made public via anonymous sources. A criminal group, whose behavior the government seeks to modify, needs to know why it is being targeted, so as to know which sorts of acts to avoid.

But if the government assault appears somewhat random, then the lesson for the gang is that they cannot hope to avoid government pressure through a less aggressive approach to their business. To a certain degree, given the notoriety of the Casino Royale fire, such a disconnect seems unlikely. However, following the initial spasm of outrage, the attack on the gambling hall has been increasingly absent from government rhetoric regarding the Zetas. The less direct the government is in linking its policy decisions to criminal provocation, the more likely the gang is to draw the conclusion that its own behavior is of secondary importance.

Another explanation is that we have not waited long enough to see the positive impact of the campaign against the Zetas. For a credible disincentive to be established and for a gang like the Zetas to adopt a less violent profile, the government must maintain the pressure for more than just a few months. According to this argument, if the government is consistent, and we are patient enough, eventually the wisdom of the dissuasive approach will become clear. And should the recent drop in murders in Nuevo Leon persist –an average of 79 people were killed in June and July– it could serve as evidence of this argument.

However, the effects of the assault on the Zetas could be interpreted as a sign that a dissuasive strategy in Mexico has little chance of altering murder rate in the immediate future. That is, while Mexican gangs may prove responsive to a system of rational incentives that punish violence and reward a low profile, such a system cannot be imposed in a short period of time. Instead, it would require years of consistent application, and wouldn’t demonstrate its efficacy so much with the gangs already being targeted, but rather through the lessons learned by their rivals and heirs: that is, the Zetas would remain a fundamentally offensive group until their disappearance, but it would fall to others to avoid the same fate via a more defensive posture.

Such a theory is, of course, not irreconcilable with the other two explanations offered above. Given that much of the faith in dissuasion comes from much its success more contained and less chaotic environments –that is, American cities, like Boston and High Point, North Carolina– it is not a surprise that there are challenges specific to its implementation in today’s Mexico.