Before, Mexican cartels could somewhat coexist with the Mexican state. But President Calderon has made Mexican sovereignty and drug cartel operations mutually exclusive. The cartels probably can't take over entire parts of the country, as their Colombian counterparts have done, but they can significantly erode the government in places like Juarez.
When a heavily armed and well-funded group fights to actively reduce the authority of the state, that's not a criminal enterprise. That's an insurgency. Mexico is not going to be able to truly gain ground against the cartels until it acknowledges that it's now fighting an insurgency. Just because the cartels are driven by money instead of ideology -- as with, say, the Taliban -- doesn't mean they can't use similar tactics and pose a similar threat.
Really, what is the difference?
Islamic extremists want us to submit to their religious dictatorship, and happily sell dangerous drugs to fund their endeavors; if the drugs destroy us, they really don't care, it would be that many fewer infidels to kill.
On the other hand, drug cartels want to sell us their wares, and if they have to destroy our society to create a market for their goods, they really don't care.
Over twenty years ago, we began to see narcoterrorism. Drug cartels in Latin America had money and drugs, so they contracted with terrorist cells, who had weaponry and manpower, against a common foe: the government. The mix has only become more potent, as now various groups occupy different parts of a continuum between politically-motivated illegal activities, and economically-motivated illegal activities.
We need to investigate and prosecute illegal activities especially where they converge. As we have learned from following the Sibel Edmonds non-case these past several years (Former FBI Translator Sibel Edmonds Calls Current 9/11 Investigation Inadequate by Jim Hogue, May 7, 2004):
JH: Can you explain more about what money you are talking about?
SE: The most significant information that we were receiving did not come from counter-terrorism investigations, and I want to emphasize this. It came from counter-intelligence, and certain criminal investigations, and issues that have to do with money laundering operations.
You get to a point where it gets very complex, where you have money laundering activities, drug related activities, and terrorist support activities converging at certain points and becoming one.