Mexico likes to blame its gun violence on the US, and gun-control advocates love to repeat the canard that 90% the weapons in Mexico come from the US.  (It’s actually less than 20%; more of them come from Mexican Army deserters.)  They’ll have a little more trouble with that argument after this weekend.  Mexico discovered that the perpetrators of several massacres are now behind bars, and were behind bars before the massacres — before prison guards let them out and armed them for their murderous rampages:

Guards and officials at a prison in northern Mexico allegedly let inmates out, lent them guns and allowed them to use official vehicles to carry out drug-related killings, including the massacre of 17 people last week, prosecutors said Sunday.

After carrying out the killings the inmates would return to their cells, the Attorney General’s Office said in a revelation that was shocking even for a country wearied by years of drug violence and corruption.

“According to witnesses, the inmates were allowed to leave with authorization of the prison director … to carry out instructions for revenge attacks using official vehicles and using guards’ weapons for executions,” office spokesman Ricardo Najera said at a news conference.

The gang at Gomez Palacio were responsible for 33 murders in three incidents, including the massacre of 17 people at a rented hall filled mainly with young adults.  They fired more than 120 rounds into the crowd; it was the bullet casings that led investigators back to Gomez Palacio.  The prison director and three of his henchmen have been placed under house arrest, although considering this story, that may wind up being more secure than prison anyway.

This should impress the truth on people, which is that the problem in Mexico isn’t American guns, or any kind of guns at all.  The problem in Mexico is corruption.  They are on their way to becoming a failed state, which is why the violence there spreads across the border — and why it’s all the more important for us to secure our side of it.