You cannot be so stupid as to think a blockade isn't an act of war! It is possible, maybe, that Mexico might permit US special forces to conduct a sweep of the cartel (I don't think they will ever do that, but it's not completely insane).
It is completely insane to suggest that Mexico, or any country in this globe, would just shrug in response to a blockade lasting.....how long, exactly? How will you even know when the cartels are wiped out? Even in Iraq, at least there was a capital that could be seized as proof of victory. Do you think the cartel leaders will just sit in their mansions like Scarface?
And if you're going to tell me that the Mexicans will just roll over in response to a blockade that will hit everyone in their country, my response is this. What determines whether a nationality is real or not, at the end of the day, is whether the citizens of said nationality are willing to fight for it. If the Ukrainians had rolled over like some had suggested they do in February 2022, that would be proof that the Ukranian identity was a fradulent construct and that Putin was right about them.
So. Do you think that the Mexican nationality is fake, and that Mexicans don't actually exist?