So North Korea says it has tested a nuclear weapon. So what? The world has known for years that this rogue nation could build the bomb and in all likelihood, already had.
"In a sense, nothing changed," says Steve Fetter, dean of the School of Public Policy at the University of Maryland, College Park. "It just demonstrated a capability that we have assumed, or should have assumed, they already had. In fact if anything, the test was probably a disappointment.
"But just as obviously, it changes everything because it must have represented a decision by North Korean leadership, and they must have known they were crossing some line. It means that this is no longer a bargaining chip."
The line that North Korea appears to have crossed was drawn in a treaty signed in 1968 to prevent the spread of nuclear weapons beyond the five nations that then had them. It has been crossed before as the nuclear club expanded to include non-signers India and Pakistan as well as, most likely, Israel. South Africa also developed weapons but gave them up, the only country to do so.
But never has that line been crossed in the totally outlaw way the North Koreans did it, not in secret, but in plain view, with practically the entire rest of the world telling them not to.
That obviously raises various dangers - could this outlaw regime use these weapons? Whom might it be willing to give them to? Could some group with no standing in the international community, and no intention other than destabilization, get its hands on a nuke? How can safeguards ensure that will not happen?
Clearly the more weapons that are out there, the more nations that have them, the greater the possibility of one of these dangers becoming reality. The response of the world to this North Korean test will speak directly to that possibility.
While the current options for dealing with North Korea appear limited since it is already so isolated and economically bereft, the dangers spotlighted by this naked violation of the anti-nuclear rule could end up strengthening the international abhorrence of developing and using such weapons, a taboo that has survived for over six decades.
"I think this may paradoxically help contribute to the nuclear taboo," says the Nobel laureate Thomas Schelling. "It is appalling to think that North Korea is getting nuclear weapons. It shows the dangers of nuclear proliferation. "
The international community would have more economic leverage against other countries. For now, with North Korea, there are few options beyond the certainty of brutal reprisals.
"The crucial thing North Korea has to understand is that if it ever uses its weapons, the entire world will want to lower the boom on them," says Schelling, who was involved in the design of the U.S. Cold War nuclear strategy and is now a professor in the economics department at the University of Maryland, College Park.
Nuclear experts say that there are many nations that could produce a bomb fairly quickly. Japan would certainly be in that group, along with Taiwan and perhaps South Korea, Sweden, Spain, Brazil and Argentina.
The fact that they haven't shows that the nuclear taboo is still strong. They understand that their status in the international community would go down if they developed a nuclear bomb, not up.
"What people need to realize is that we are dealing here with marginal cases," John Steinbruner, director of the Center for International and Security Studies at the University of Maryland, says of countries like North Korea and Iran. "There are 189 countries signed up to the treaty and probably 30 or 40 of them could have nuclear weapons a hell of lot more readily than North Korea. Japan could get them in a few months if it wanted to."
Schelling agrees. "These countries do not need to prove that they are capable of that; everybody knows they are," he says. "North Korea shouldn't get any respect because it can explode what may be a half-kiloton device. These countries could probably have done that 30 years ago, and could now do it in some weeks or months. But they don't need to do that to try to measure up agains the North Koreans, to prove that we are their equal."
North Korea has essentially been playing its nuclear poker hand, one card at a time, for a couple of decades. Its potential - and now real - bomb was designed to bring it security. In reacting to its test, the rest of the world faces difficulties that would be the case with almost any other country that could develop these weapons.
For one, economic sanctions have little effect on a country that essentially has no economy.
"Talking about squeezing the North Korean economy is like talking about squeezing a stone to get water," says Fetter, a trained physicist who is widely published on nuclear proliferation issues.