How scared should you be about North Korea?

By Jake Tapper and Sherisse Pham

Sources tell CNN that top national security officials are quite concerned that North Korean leader Kim Jong Un will do something rash. The hermit kingdom routinely threatens to annihilate South Korea, with whom it is technically still at war, Japan, and the United States. There were bloody sea battles between North and South Korea in 1999, 2002, and 2009. In 2010 North Korea attacked a South Korean ship, killing 46 sailors, and then a few months later, a South Korean island, killing four people. The attack on the island took place weeks after annual military drills by South Korea and the United States. So how scared should the U.S. be about North Korea? We'll take a serious look at this question on our show, The Lead with Jake Tapper, at 4pm ET on CNN today, with our guest former Secretary of Defense William Cohen.

North Korea's official state media released new photos overnight, showing its young leader sitting at a desk leafing through papers as four elderly military officials stand nearby. Another photo shows a military official standing in front of a chart with Korean characters that read "U.S. Mainland Strike Plan." North Korean state media also said on Friday that North Korea's leader approved a plan to prepare standby rockets to hit U.S. targets, after American stealth bombers carried out a practice mission over South Korea.

So is the U.S. prepared for a North Korean attack? According to Paul McLeary of Defense News, the U.S. Army may in fact be ill prepared for such an attack. A recent war game conducted by Army planners assumed the collapse of "North Brownland," a very North Korea-like country that inconveniently loses control over its nukes as it falls. When American forces made it over the border into "North Brownland," they encountered several humanitarian assistance problems, and major tactical complications caused by not having human intelligence assets in the country for years.

The good news for the people who conducted that war game is that there is a good chance North Korea is bluffing about war, as Max Fisher points out in the Washington Post. For one, everything North Korea is doing now - cutting off communication with South Korea, issuing increasingly ominous threats - it has done before. For another, the Kaesong Industrial Complex, located just across the northern side of the border, is still up and running. The complex, writes Fisher, is staffed by South and North Koreans, and cannot function without Pyongyang's daily approval. If it is shut down, then we have something to worry about.

The White House maintains that the United States is ready for an attack from the hermit kingdom.

"We're going to be prepared for any contingency from the North Koreans," McDonough said on CNN's "The Lead with Jake Tapper" last week.

"The kind of antics and the kind of language that we've heard from Kim Jong Un ... are the kind of actions that don't connote strength, but rather connote some kind of weakness, and some frankly outlandish behavior," McDonough added.

Indeed, a photo released earlier this month from North Korea showing a military exercise appears digitally manipulated to show more strength and resources.

"We'll be ready for every - other developments, as well. That's why we've worked very closely with the Japanese, with the South Koreans," said McDonough.

Our interview with former Secretary of Defense William Cohen airs at 4pm today on CNN.