Fire every judge who has any suspicion of wrongdoing.
Fire every law enforcement officer who has any suspicion of wrongdoing.
Set up a few base camps from which the United States may launch 'Kinetic Military Actions' against drug gangs.
Oversee fair elections.
Stay for a while and wring the damned drug gangs out of that country.
It would be a much tougher go than Afganistan and Iraq, but the payoff would be higher.
Not seeing a flaw in your plan/logic.
We would have to stay in Mexico forever, corruption is ingrained, I have been told he came with the Spanish. You know how long they have been gone and the corruption is still there. Everybody with any station in Mexico has their hand out.
If you do that you live with the consequences. Ignorant populations will give you elections like in Gaza where they all voted for Hamas, or the United States where they all voted for American Idle.