In modern Mexico, this system attempts to ensure that services are rendered to certain people. As in colonial times, it also attempts to make up the shortfall in salaries. I have personally heard Mexican government officials say that corruption is almost a necessity in Mexico to maintain order and stability. It is seen as a way of life. As long as most people feel they are getting their share - even if it is through corrupt means - then it keeps the masses happy.
Another angle of corruption in Mexico is the dreaded plata o plombo - "silver or lead," meant as take the bribe or take the bullet. This is a form of corruption encouraged by fear, as opposed to social acceptance or economic survival. Many police officers in Mexico are corrupt because they or their families are physically threatened by DTO members. Public executions of over 450 police officers and soldiers in Mexico last year are proof that the DTOs are more than willing to make good on their threats.
So how does the Calderon administration, which is so committed to cleansing Mexico of this endemic corruption, accomplish this goal? The sad fact is, it can't. Calderon is up against roughly 500 years of history ingrained into his people. He also has two other major things working against him: the economy and an organized crime crisis. If the average Mexican citizen could make a fair living by living fairly, then corruption wouldn't be seen as necessary. While corruption exists in the United States (and every country, for that matter), it exists to a much smaller extent because public servants - for the most part - earn a fair salary with which they can make a living. The Mexican economy is the 12th largest in the world, but the country has an extremely high rate of underemployment, and most people do not earn what Americans would call fair salaries for their work. Unless economic conditions in Mexico improve, the economic challenge to eliminating corruption will remain. The organized crime threat from DTOs is so pervasive, few public or law enforcement officials in Mexico can escape it. When accepting a bribe is a matter of life or death, rather than being honorable or corrupt, the choice is easy for many. Mexican society may not see this as a form of corruption as Americans do, since it is a manner of survival that American cops don't have to deal with. Regardless, the unreliability of Mexican law enforcement is the largest obstacle Calderon must face. Short of removing the large majority of Mexican law enforcement from their posts, which is impractical and probably impossible, Calderon will have to continue to rely on the more reliable, very loyal, and considerably less corrupt Mexican Army as the only stop-gap measure at his disposal.
Mexico's Drug War: IN FOCUS: Corruption in Mexico