Ney González indicated that "in Nayarit the only thing that is working in combating crime is the support we receive from the navy, the army, and the Secretariat of Public Security", and that in his government "we do our part, but our police, for some strange reason, always arrives 20 minutes after some violent act has occurred".
Efficacy to one side, if a new president came in and loudly announced the removal of half of the federal troops from the states, he would be extremely vulnerable to all manner of political attacks from politicians across the nation. Every violent act could be blamed rather directly on the president's decision, and one would have to naive to think that governors and mayors and local police chiefs would be hesitant about shifting blame toward the prez. The only way such a decision would feasible politically is if it was accompanied by a dramatic reduction in violent crime, which would not be a foregone conclusion. In other words, a dramatic de-escalation of anti-organized crime operations would be a tremendous gamble with a potentially huge downside.
González's quote also demonstrates how the governing ethos in Mexico is much more focused on the central government. He basically pleads impotence with regard to the police that operate in his state, but it's not like his hands are completely tied. He's the governor! Yet, his first point of reference (and that of many of his counterparts from all parties and from around the country) on security in Nayarit is the federal government.