By Ted Galen Carpenter, Special to CNN

Ted Galen Carpenter, a senior fellow at the Cato Institute, is the author of nine books on international affairs, including the just released The Fire Next Door: Mexico’s Drug Violence and the Danger to America. The views expressed are his own.

A striking feature of the presidential debate on foreign policy was the total lack of attention given to Latin America –notably the drug violence wracking our next door neighbor, Mexico. Nearly 60,000 people have perished since 2006 in the Mexican government’s military-led offensive against the country’s powerful, ruthless drug cartels. But while President Barack Obama and Mitt Romney both obsessed about the Middle East, they virtually ignored Washington’s relations with our southern neighbors. After a brief observation from Romney near the start of the debate that the region offered important – and neglected – economic opportunities for the United States, both candidates quickly abandoned the Western Hemisphere.

That was extraordinarily myopic. Given its geographic proximity, historical ties, and mounting importance as an arena for trade and investment, Latin America should be high on Washington’s diplomatic and economic agenda. And near the top of the national security agenda should be the alarming developments involving the drug violence in Mexico.

Killings continue to rise, and hardly a week passes without a new report of grisly acts south of the border. Portions of several key cities, especially Ciudad Juarez and Monterrey, are now virtual war zones. The Mexican government’s control is becoming precarious in major swaths of territory, including the crucial northern states of Nuevo Leon, Chihuahua, and Tamaulipas. Several of the cartels, especially the Sinaloa cartel and the ultra-violent Zetas, pose a threat to the integrity of the Mexican state.

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Equally troubling, the turmoil in Mexico is spreading to Central America and beginning to seep over the border into the United States. One would think that such a national security problem would merit some attention from the incumbent president and the man who aims to replace him.

Indeed, Mexican opinion leaders were justifiably miffed at the failure to address the drug war. Prominent journalist Leon Krauss’s widely circulated tweet summarized the frustration. “Mexico, facing 100,000 deaths, neighbor to the United States, didn’t deserve a single mention tonight. A disgrace.”

Mexico’s problems with the Sinaloa cartel and the Zetas are now plaguing the countries of Central America. According to Leonel Ruíz, Guatemala’s federal prosecutor for narcotics offenses, the Zetas had gained control of nearly half of Guatemala’s territory. Kevin Casas-Zamora, a former vice president of Costa Rica, suggest the figure is about 40 percent.

The cartels’ penetration of Honduras and El Salvador has also reached the point that in significant portions of those countries governmental control is eroding or already nonexistent. El Salvador’s president, Mauricio Funes, admits that the Zetas successfully bribe elite police units with $5,000 monthly payments to cooperate with the cartel and to steal high-powered weapons and grenades from the military. Honduran President Porfirio Lobo argues that in his country, drug gang members now outnumber police officers and soldiers.

Even Costa Rica, long an enclave of democracy and stability in the region, has come under growing pressure. The drug trade there is more prominent than ever before, and the Obama administration for the first time put that country on the official list of “major drug transit or major drug-producing countries.”

Most importantly, Mexico’s troubles are also beginning to afflict the United States. According to law enforcement authorities, Mexican drug organizations now have ties to criminal gangs in at least 230 American cities, including all of the 50 largest cities. The cartels’ presence now even extends to relatively small cities and, in some cases, to rural counties – and not just in the southwestern states, but portions of the South, the Midwest, and other regions.

People in impoverished Mexican-American communities along the border are feeling the menace of drug cartel enforcers. As Associated Press correspondent Paul Weber reported from Fort Hancock, Texas: “When black SUVs trail school buses around here, no one dismisses it as routine traffic. And, as I've noted before, when three tough-looking Mexican men pace around the high school gym during a basketball game, no one assumes they’re just fans…Mexican families fleeing the violence have moved here or just sent their children, and authorities and residents says gangsters have followed them across the Rio Grande” in a campaign of intimidation.

Even Anglo populations along the border are becoming nervous. Complaints are surging from ranchers in the borderlands of Arizona, New Mexico, and Texas that intruders use their properties with impunity as routes to enter the United States. And the level of fear is rising as more and more of the uninvited seem to be involved in drug smuggling rather than being ordinary people looking for work and better lives in the United States.

While Romney and Obama obsess about Iran, Syria, Afghanistan, and virtually every development in the Middle East, North Africa, and Central Asia, we have a significant security problem brewing much closer to home. Yet that issue did not merit even a single sentence in a presidential debate supposedly devoted to foreign policy. That is a classic case of blind spots and misplaced priorities. But the candidate elected president on November 6 will not have the luxury of ignoring the drug violence on our southern border.