Sad that such an obvious thing has taken so long, but great news, especially for Mexico. The first step to taking down/limiting the power of the cartels is to cut off their funding, which primarily comes from marijuana. Less funding means less money for bribing politicians and law enforcement, and less money for purchasing firearms.
"Oh, but they'll just move on to other crimes, like kidnapping," idiots will say. If those activities were as profitable, they would be doing that instead of wasting time smuggling marijuana. The problem isn't that Mexico is full of criminal masterminds that can't be stopped, it's that those criminals are fucking rich and it's because of us.
I'm happy to see that we're finally doing something about it, even if it's for other reasons.