Fighting a two-front war is ill-advised, as Napoleon Bonaparte, Kaiser Wilhelm and Adolph Hitler all found out the hard way. But the U.S. is now facing an unprecedented triple threat. But with combat troops already stationed in Iraq and Afghanistan, President Obama has largely ignored what Rep. Ted Poe, R-TX, calls the silent third front, our1,951-mile border with Mexico.

Poes war reference is meant to be taken literally. Members of increasingly bold Mexican drug cartels have already killed more than 18,000 Mexicans and 79 Americans. More than 5,000 people were murdered in Ciudad Juarez alone over the past three years, including two U.S. consulate employees Poe says were deliberately targeted for execution in March, sending a clear but chilling message to U.S. authorities.

But when Texas Gov. Rick Perry asked Homeland Security Secretary Janet Napolitano to send unmanned drones and 1,000 additional soldiers to assist beleaguered Border Patrol agents and local sheriffs, he was rebuffed.

Instead, Napolitano announced she was canceling the virtual border surveillance project, leaving states that have to deal with the unending illegal flow of people, drugs, money and guns every day largely on their own.

Border county sheriffs tell Poe they are outmanned, out-financed and outgunned, unable to keep cartel thugs out of the U.S. despite hundreds of millions already spent on a wall, cameras and other security measures. Those cameras dont do any good if you dont have somebody to pick [border crossers] up, Poe told The Examiner. By themselves, cameras dont capture anybody except on film.

What cameras have captured, however, is unmistakable evidence that Mexican military helicopters are entering U.S. airspace with impunity. American sheriffs have given Poe evidence of two such incursions during the last three weeks.

One chopper was photographed hovering over a building; the other over an RV park. We dont know what their intention was, Poe noted, adding: The Mexican military has no business coming into the United States. But that obviously didnt stop them from doing so anyway.

The third front is becoming every bit as violent as Iraq or Afghanistan. For example, 30 residents of El Porvenir, a small Mexican town located about four miles south of the Texas border town of Fort Hancock, asked for political asylum after the drug cartels reportedly threatened to start killing schoolchildren unless their parents paid 5,000 pesos in protection money.

One elementary school teacher in Fort Hancock told Fox News that her second graders constantly record grisly details of relatives being murdered and their homes burned in their daily journals. Kidnapping children from wealthy Mexican families and holding them for ransom has become standard operating procedure in some Mexican villages. So has beheading.

Poe believes that more violence will inevitably spill over into American communities unless immediate steps are taken to seal the border. Homeland Security can say whatever they want, Poe told us, but theres a new sense of urgency as drug cartels ratchet up the violence on the Mexican side. People are not only sneaking into the United States, theyre shooting their way in.

Theres a word to describe uninvited and repeated border incursions by foreign military operatives and well-armed members of organized crime. Far from doing much of anything to stop it, the Obama administration wont even admit that the U.S. is being invaded.

Barbara F. Hollingsworth is The Washington Examiners local opinion editor.