Texas Governor Rick Perry has a solution for the drug violence in Mexico: send in the troops!

American troops, that is.

"It may require our military in Mexico working in concert with them to kill these drug cartels and keep them off our border," he said.

Perry was speaking at a campaign stop when he shared this idea. He's currently the frontrunner for the Republican nomination for president, according to a recent poll.

The U.S. of course has spent billions on the drug war, and much of that money has gone to support Mexican security forces and to share intelligence. It has also deployed drones to survey the border.

But none of that comes close to what Perry appears to be suggesting, which is a deployment of American troops on sovereign territory next door.

Here he is, explaining his plan:

"I don't know all the different scenarios that would be out there," he said. "But I think it is very important for us to work with them to keep that country from failing."

The Mexicans aren't likely to be so receptive to the idea.

Perry probably knows this from his high-school history class, but the U.S. and Mexico fought a war over territory in 1846. At the time, Mexico controlled what is now the southwestern U.S. The furor started with a battle over land that includes part of modern-day Texas.

It ended with the U.S. controlling the land it does now — a massive loss for Mexico. Massive as in, their territory was nearly cut in half.

So the idea of Mexican sovereignty is kind of important today.

It's unclear whether Perry really means what he says. It's likely that he is looking for a way to sound tough on immigration and border problems. He has taken flak recently among Republicans for approving a measure in Texas to allow children of illegal immigrants to attend college at the in-state tuition rate.

Meanwhile, Mexico's President Felipe Calderon offered another solution: the U.S., he suggested, should consider legalizing marijuana to cut down on cartel profits from that trade. The U.S. creates a huge demand for marijuana and cocaine, which the cartels in Latin America readily supply.

We can guess what Perry thinks about that one.