Looking through the National Drug Threat Assessment, I found some of the developments interesting.
On the east coast of the US, local distributors are now bypassing the Colombians for their cocaine and going straight to the Mexicans. That seems backward, given that Mexicans get their cocaine from the Colombians in the first place, until you realize just how powerful and organized the Mexicans are. Any Colombian supplier dealing directly with a US distributor is actually bypassing the now-traditional route through the Mexicans, so the Colombian isn't necessarily as secure a source. The Mexicans can better guarantee delivery and protection.
In the 1980s, the Colombians began giving Mexicans increased control over cocaine, to the point that now, Mexicans control much of the delivery all the way from Colombia itself. They've shored up the route; any Colombian who tries to revert to the old way is taking a huge risk. Impressive gains by the Mexicans.
Italian organized crime outfits are also decreasingly involved in drug trafficking, the report notes, as the Mexicans take over their turf too. I see this as possibly big news for the future: the Italian organizations in the US still have ties to much of Europe. If the Mexicans take over their drug racket in the US, and make some sort of alliance, they could use those ties to distribute cocaine directly to Europe, too. The Colombians would be relegated to mere producers, and the Mexicans would traffic it.
The last thing that I thought interesting was that Mexican traffickers are increasingly using ships and submarines to smuggle their drugs to the US. The Colombians have long used these; the Mexicans have largely stuck to overland routes and on occasion, planes.
The use of maritime vessels is interesting: getting drugs across the border is pretty easy, why the need to go by sea? My thinking is that this might be a pre-emptive move: noting that the border is attracting so much attention, the Mexican cartels are trying out new routes. When the US Coast Guard cracked down on the Caribbean in the 80s and 90s, the Colombians did the same and discovered Mexico. Now that the border is being scrutinized, the Mexicans are themselves eyeing new options.