There is something really strange about North Korea bearing its chest like this.

No there's not. They do something similar every time sanctions are going on. It's their way of negotiating.

From the New York Times report on the topic published today, North Korea Calls Hawaii and U.S. Mainland Targets:

The threat from the North’s Korean People’s Army Supreme Command came only hours after President Park Geun-hye of South Korea warned that the North Korean leadership could ensure its survival only when it abandons its nuclear weapons, long-range missiles, provocations and threats. [.....]

Tensions on the Korean Peninsula have risen after North Korea’s launching of a three-stage rocket in December and its third nuclear test last month. In response, Washington and Seoul pushed for a United Nations Security Council resolution imposing more sanctions on North Korea and this month began their annual joint military drills intended to warn North Korea against attacking the South.

North Korea has since issued a torrent of threats to turn Washington and Seoul into a “sea of fire.” Its leader, Kim Jong-un, who has inherited the "military first" policy of his late father, Kim Jong-il, has made a round of visits to military units in the last week

Bill Clinton explained the real problem with North Korea  nukes  & missiles very well back in 2003 on the teevee, I'll never forget it, and I think the explanation still works well. Not that they can hit the US, but that they can sell the nukes. (BTW, his opinion on what to do about Saddam Hussein at the time is also in the interview:)

The relevant excerpt, my bold:

KING: You mentioned North Korea. How serious is this?

CLINTON: I think it's very serious.

First of all, let's make sure the people listening to us understand what exactly has happened. North Korea is a poor country with about 17 million people and about a million and a half or a million seven in the army. Over a million of them very close to Seoul, South Korea.

They know they can't win a war in the end, but they could do a lot of damage. They can't grow their own food. It's the most isolated society in the world. When their soldiers defect sometimes they weigh less than 100 pounds. Their only cash crops are bombs and missiles. They're great at it. They're really good at bombs and missiles. But they know they can't use them except to sell them because they need money.

China, for example, long a sponsor of North Korea, now does 10 times as much trade with South Korea as North Korea. So nobody in the region wants them to have the weapons. The main reason they had weapons or missiles was either to sell them or to be paid not to sell them and to be recognized as important. Their objectives are to survive with food and energy and not to go the way of East Germany. They don't want to go away.

So, in '94, we found out they would have the plutonium power planks and you can take the spent plutonium rods, after you generate electricity, and still have enough to make a lot bombs. We had a tough time with them, but we got them to end that program and they kept it ended until apparently today they started again. They would have 100 hundred weapons if we hadn't done that.

And then in '98 we got them to stop testing long-range missiles and in 2000 we nearly got them to end the missile program. It turns out they had this smaller laboratory program to develop a nuclear bomb with enriched uranium.

KING: So what do you do?

CLINTON: So what we should do, in my opinion, is get their neighbors, first of all, beginning with the South Koreans, and then the Japanese ,who tried to make up with them. The prime minister of Japan took a very courageous and controversial trip to North Korea. And the Chinese and the Russians and get them all together and say, Look, here's the deal. We'll make an omnibus agreement if you'll end both nuclear programs, let testing in so you can't start any thing again, end the missile program, something that they had not agreed to do. And we'll make sure you got enough food and energy. We'll teach you how to grow food and we'll give you a non-aggression pact. They want this non-aggression pact, I think that's a no-brainer. Why? Because if we ever had to attack it would be because they did some thing that violated the non-aggression pact. KING: Right.

CLINTON: So, I think that the diplomatic course is right -- the president and the administration has said that they want to handle it diplomatically. But I think you have to firm in public and absolutely brutal in private. You cannot let them become a nuclear arsenal, because the pressure on them to sell these bombs will be overwhelming. They have no other way to make money.

KING: And who do they sell them to?

CLINTON: Well, you tell me.

I mean, you know, we found some missiles they were selling to Yemen not very long ago and put the president in a terrible bind because the Yemenis had helped us get the people that blew up the USS Cole shortly before I left office.

But this can be handled diplomatically as long as there -- we should not take the threat off the table and we shouldn't think we're bribing them if we get something we didn't have before. We can't pay them twice for the same thing. But if we can make a comprehensive settlement that says, Here's the way you can be part of the East Asian community. Here's the way you can be part of the world community. And here's what you have to do. That's what I think we ought to do.

Edit to add: you titled the post well.

The U.S.'s answer:

U.S. Begins Stealth Bombing Runs Over South Korea

By Choe Sang-Hun, New York Times, March 28/29, 2013

SEOUL, South Korea — The American military made a rare announcement that two nuclear-capable B-2 stealth bombers ran a practice bombing sortie over South Korea on Thursday, underscoring Washington’s commitment to defend its ally amid rising tensions with North Korea.

The two B-2 Spirit bombers made a nonstop round trip from Whiteman Air Force Base in Missouri, demonstrating the United States’ ability to “provide extended deterrence to our allies in the Asia-Pacific region” and to “conduct long-range, precision strikes quickly and at will,” the American command in the South Korean capital, Seoul, said in a statement.

It was the first time the American military publicly confirmed a B-2 mission over the Korean Peninsula. As the bombers dropped inert munitions that they carried 6,500 miles over the Pacific to an island bombing range off South Korea’s west coast, Secretary of Defense Chuck Hagel conferred with his South Korean counterpart, Kim Kwan-jin, on the phone, reaffirming the United States’ “unwavering” commitment to defend the South.

After suffering from the American carpet-bombing during the 1950-53 Korean War, North Korea remains particularly sensitive about American bombers. It keeps most of its key military installations underground and its war cries typically reach a frenetic pitch when American bombers fly over South Korea during military exercises. The resulting fear and anti-American sentiment is used by the regime to make its people rally behind the North’s “military-first” leadership.

Both B-52 and B-2 can launch nuclear-armed cruise missiles. The Pentagon used their training sorties over the Korean Peninsula to highlight the role the long-distance strategic bombers play as part of Washington’s “nuclear umbrella” over South Korea and Japan [....]

http://globalpublicsquare.blogs.cnn.com/2013/03/28/no-north-korea-cant-h...

North Korea's announcement via state TV that it was preparing to target Guam, Hawaii and the continental United States – and had readied its “rocket and long-range artillery” forces for the purpose – has inspired a cacophony of speculation across the globe.

But the fact is that despite the bombast, and unless there has been a miraculous turnaround among North Korea’s strategic forces, there is little to no chance that it could successfully land a missile on Guam, Hawaii or anywhere else outside the Korean Peninsula that U.S. forces may be stationed.

North Korea doesn't appear to have the capability to carry out its latest threat to attack U.S. bases in Hawaii, Guam or the U.S. mainland. From what we know of its existing inventory, it does have Scud derived missiles that could complicate the situation on the Korean Peninsula, and they could likely reach Japan. But anything further is probably an empty threat.