system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If Mexico legalizes marijuana how will this impact the illegal drug trade between mexico and the US, the DEA, etc.?
gpt
Depends on how they legalize it.  If they just 100% legalize it and don't regulate it then nothing will change because it would still be cheaper to buy marijuana from mexico on the street than buy it at a legal pot shop in the US.  Also there is still the demand for marijuana in states where it is still illegal and it's way cheaper to buy and smuggle mexican marijuana than smuggling in stuff from legal pot shops.  Mexico would have to regulate and tax it to the point that it isn't worth the trouble to try and smuggle it into the US.

The other thing that isn't being considered are the other drugs.  Things like cocaine from south america end up going through mexico to get to the US.  So even if marijuana is legalized and regulated to the point that cartels can't make money on it, the cartels will just shift focus to smuggling more cocaine, meth, haroin, etc.