What Would Happen if North Korea Attacked?

A nighttime satellite photo of the Korean Peninsula reveals the stunning gap between the modern South and the black hole that is North Korea. How can a country which can barely keep the lights on even think about starting a war?

"If the North starts anything, the North loses and I believe that firmly," said John Tilelli.

Tilelli believes that based on his three years as the commanding General of the U.S. and South Korean forces.

"If this were to happen, is this a short war or a long war?" asked CBS News correspondent David Marin.

"I think it is a short war," Tilelli said.

It would be a contest of mass. The North Koreans have a million men under arms against the technology and training of 28,000 American and half a million South Korean troops.

But the North Korean advantage in numbers would be quickly overwhelmed by U.S. reinforcements and airstrikes from as far away as Guam or as close in as submarines off the coast.

So what could the leaders of North Korea possibly hope to achieve in a war they know they cannot win?

"Their hope is that they can make the war so painful to the United States and South Korea that we will not pursue it to the end," said Joseph Bermudez.

Bermudez tracks the North Korean military for Jane's Defense Weekly believes it would begin with a massive barrage by thousands of artillery pieces and rocket launchers, many of them capable of hitting the capital of Seoul, a sprawling megalopolis of 13 million people just 20 miles south of the DMZ.

"They intend to employ chemical weapons, ballistic missiles right from the very beginning," Bermudez said. "If they feel threatened enough, they might even go nuclear. We're not sure."

The U.S. has long since pulled its nuclear weapons out of South Korea but the threat of retaliation against a nuclear or chemical attack still stands.

"The United States has made it clear for many years it reserves the right to respond with overwhelming force to the use of weapons of mass destruction against the United States, our people, our forces, and our friends and allies," Defense Secretary Robert Gates said last year.

Even without nuclear weapons, a conventional war on the Korean Peninsula would be horrific.

"The consequences are extreme," Tilelli said.

"Extreme in causalities?" Martin asked. "What are we talking about here?"

"I would say it would be in the tens of thousands," Tilelli said.

North Korea's artillery barrage would be met with an immediate counter-attack by South Korean and American artillery and aircraft with precision guided weapons.

But North Korea's artillery is not an easy target. Much of it is dug into the sides of mountains.

"They are able to open the doors, the blast doors, move out, fire a set number of rounds and then return under cover," Bermudez said.

North Korean tanks would come south through three corridors. One of them is a major north-south highway. All of them heavily fortified and mined with charges to collapse bridges and overpasses.

Its infantry would come pouring through secret tunnels dug beneath the DMZ. Special operations forces would land in miniature submarines behind the front lines.

"This combination is hoped by the North Koreans to totally throw off the defending forces and give them the opportunity to penetrate quickly and deeply. That's their hope," Bermudez said.

Wars never go according to plan, but in the end the South would win and the North would lose, and it would be a disaster for all sides.