North Koreans have formally ended their three-year mourning period for Kim Jong-il. By custom his son, Kim Jong-un, and the country now are free to move forward without hindrance from the past.

A small, poor nation, the Democratic People’s Republic of Korea should be an international nullity, irrelevant to global affairs. Yet it again dominated headlines in the U.S. with the hacking of Sony.

Although the FBI is pointing its finger at Pyongyang, a number of online experts strongly doubt the charge. Whatever the case, this otherwise two-bit international player is at the top of the news.

For the last seven decades Washington has made North Korea America’s problem. The U.S. initially had little choice since its joint division of the Korean peninsula with the Soviet Union led to creation of two antagonistic states.

But eventually the Republic of Korea took off economically and adopted democratic rule. Today the ROK surpasses the North on every measure of national power save military, and the latter is a matter of choice.

As I point out on Forbes online: “By taking on responsibility for South Korea’s defense, Washington has thrust itself into the middle of the Korean conflict. The risk and cost made sense during the Cold War when the ROK was vulnerable and the region a hegemonic battleground. But no longer.”

Washington should extricate itself from the Korean imbroglio while giving the North something to lose should it consider cyber attacks or other threatening behavior in the future.

The first step is to turn South Korea’s defense over to South Korea. American taxpayers no longer need pay to defend the ROK, which has more than enough resources to defend itself.

U.S. forces should come home and the misnamed “mutual” defense treaty should be turned into a cooperative pact involving base access and intelligence sharing. Washington should sell the ROK any weapons it desires.

American officials also should raise the prospect of a nuclear South Korea. Ever fewer analysts believe that Pyongyang will give up its nuclear weapons voluntarily. The regime still might be persuaded to freeze its capabilities, but that objective is most likely to be achieved with China using its economic clout against the North and Seoul threatening to develop a countervailing arsenal—which would have the salutary effect of encouraging Beijing to act.

Paradoxically, at the very time North Korea looks more intransigent than ever, the Obama administration should indicate its willingness to initiate low-key diplomatic relations. Switching course toward the North would open a small window into North Korea. Doing so also would test the regime’s willingness to develop a more normal relationship.

Perhaps most important would be to create a benefit and the potential for additional gains which Pyongyang could lose. With neither diplomatic nor commercial ties to the U.S., the DPRK has little to deter it from staging a cyber attack (whether or not it is responsible for Sony’s travails) and behaving badly in other ways.

Kim Jong-un has a reason to respond favorably. North Koreans are doing better economically, which will raise expectations that might be hard to satisfy.

Another important factor is geopolitical. Beijing only grudgingly supports its long-time ally. North Korea always has balanced its closest patrons, both the PRC and Soviet Union.

Improving relations with America would be another way to increase Pyongyang’s leverage. Burma has taken a similar approach. Washington should offer the same possibility to the North.

Of course, no one should expect the speedy development of a democratic, capitalist, pro-American government in the DPRK even in the best of circumstances. But present policy isn’t working.

North Korea is an international problem with no good solution. Washington should cheerfully, even eagerly, pass off responsibility for dealing with the North to the latter’s neighbors, including the PRC.