Mexico is not a good place to visit. While I love a good, authentic taco as much as the next guy, the truth is that the nation to our immediate south is anything but a safe place for Americans. Or, frankly, anyone else for that matter.

As if the history of violence in the border areas weren’t enough for you, though, we now learn that at least 21 people have been killed in clashes between cartel forces and the Mexican police.

Mexican security forces on Sunday killed seven more members of a presumed cartel assault force that rolled into a town near the Texas border and staged an hour-long attack, officials said, putting the overall death toll at 21. The Coahuila state government said in a statement that lawmen aided by helicopters were still chasing remnants of the force that arrived in a convoy of pickup trucks and attacked the city hall of Villa Union on Saturday.

Gov. Miguel Angel Riquelme said late Sunday afternoon in a statement posted online by the state government that authorities had determined the casualty count from the gun battles stood at 15 gunmen dead and four police officers killed. He said two civilians also were slain by gunmen after being abducted.

The governor said six more officers were wounded as were four young people who had been taken by the attackers.

Francisco Contreras, an official in the state security agency, said later that the two slain civilians were a firefighter and an engineer who worked for the municipality. He said a second firefighter was missing.

The reason for the military-style attack remained unclear. Cartels have been contending for control of smuggling routes in northern Mexico, but there was no immediate evidence that a rival cartel had been targeted in Villa Union.

The governor said the armed group — at least some in military style garb — stormed the town of 3,000 residents in a convoy of trucks, attacking local government offices and prompting state and federal forces to intervene. Bullet-riddled trucks left abandoned in the streets were marked C.D.N., the Spanish initials of the Cartel of the Northeast gang.

If you didn’t know all you need to know about how little respect the cartels have for the Mexican government and their ability to enforce drug laws, the fact that they’re putting their initials on vehicles should tell you plenty.

That said, it does look like the police came out on top in this one. It was ugly and violent, but you’ve got a lot more bad guys dead than good guys. That is, ultimately, a win.

Further, I suspect you’re going to have to see a lot more of this kind of thing before Mexico improves.

What we’re seeing here is, more or less, a civil war. The cartels view themselves as a government unto themselves and are fighting the lawful government in Mexico. They’re aided by a number of factors, including a history of corruption and a disarmed populace who has no choice but to cower in fear when faced with the violence.

The fact that cartels are labeling equipment with their initials similar to a logo almost suggests they view themselves as a military force in their own right.

Putting them out of business is going to require a lot more violence, I’m afraid.

Violence is the only real language the cartels understand.