NEW YORK — Why is a pair of American warships shadowing a North Korean rust-bucket called the Kang Nam I as it makes its way from the Sea of Japan toward Southeast Asia?

American intelligence officials believe the ship carries illicit arms meant for the military dictatorship in Myanmar. Or, hint anonymous “intelligence sources,” perhaps impoverished, pariah state Myanmar is just a way station for a more nefarious technology transfer.

Sadly, the world probably will never know which is the case.

New United Nations Security Council sanctions passed after North Korea tested its latest nuclear warhead authorized the world’s navies to monitor such traffic. China, which has traditionally protected Pyongyang from the harshest Security Council rebukes, even voted for the sanctions this time, a significant symbolic shift and a victory for U.S. diplomacy.

But Beijing still blocked efforts to authorize boarding parties to inspect suspect North Korean vessels. For that to happen, North Korea would have to give its permission, which is about as likely as Kim Jong Il turning up at the next board meeting of Human Rights Watch.

Such is the infuriating status quo at the U.N. Even a nuclear explosion by a nation that sells its nuclear knowledge to the highest bidder, shoots poorly engineered missiles over their neighbors’ heads and treats its own population like prison inmates could not bring coherent action from the Security Council.

And so Barack Obama finds himself in a familiar position for an American president. Having seen a diplomatic initiative spurned with a nuclear test, he talked tough and did due diligence by working through the existing U.N. channels. And for his pains, he finds himself with less leeway to deal with a ship that might (though it is unlikely) be carrying a nuclear weapon than he had with a bunch of teenaged Somali pirates.

It did not take long for Obama’s domestic enemies to gloat. Smarting from the years in which their own approaches (including diplomatic quarantine, covert action, and preemptive warfare) failed, they were loath to see Obama’s squishy diplomatic initiatives bear fruit. How happy they must now be.

Still, with the exception of the one-third of Americans who constitute the permanently embittered minority, reasonable people should have some pity for Obama at this stage.

Inheritor of a zombie banking sector, a seized-up auto industry, two raging wars, and poisonous hands in Iran and North Korea, he’s had little time to put a stamp of his own on world events.

And the best case scenario for many of these problems is slow, gradual improvement. For some, including Iran, North Korea, and aspects of the global economy, improvement depends less than ever on America’s actions.

George H.W. Bush could shoot for a “new world order.” Bill Clinton’s secretary of state, Madeleine Albright, called America “the indispensible nation.” George W. Bush created the “indefensible nation.” Now Obama must salvage what he can of the goodwill the U.S. took with it out of the 20th century.

Obama's speech in Cairo invited the Muslim world to end the “cycle of suspicion and discord” that has characterized relations with America since the end of World War II. He recorded a video message for Iran promising a “new beginning” and sent feelers to Russia. Both were spurned.

Truman-like, he sacked a highly decorated commander of the Afghan war and replaced him with Gen. Stanley McChrystal, a counterinsurgency specialist whose own writings on the topic echo the “smart power” approach espoused by the new White House.

Obama promised to keep his promise to get U.S. forces out of Iraq — well, all but 50,000 of them — and he shows signs of reversing America’s disgraceful reputation as a leading global polluter.

All of these made good sense as first steps. Now, each demands a second step which is far, far more difficult to achieve.

With regard to North Korea, that decision may be only hours away. As the Kang Nam chugs toward its destination — probably the Myanmar port city of Thilawa — Obama faces a delicate decision. Should he order the Seventh Fleet to go beyond the U.N. Security Council’s writ and board the Kang Nam? Facing a much more serious (and well-documented) risk, John F. Kennedy did precisely that during the Cuban Missile Crisis in 1961.

Yet to follow that course today runs the risk that the increasingly irrational North will respond with a wild retribution of some kind against South Korea and the American troops based there. The North need not go nuclear to cause thousands of deaths. Within the range of its tens of thousands of artillery tubes on the 37th parallel is the entire city of Seoul and some of the U.S. garrison, too.

“What we're not going to do is to reward belligerence and provocation in the way that's been done in the past,” Obama said, a reference to the sand Kim Jong Il kicked in the eyes of both Clinton and Bush after previous American initiatives were spurned.

What then, Mr. President, will North Korea’s reward be this time? It’s a very dangerous moment, indeed.

Michael Moran is Foreign Affairs Columnist for GlobalPost and executive editor of RGE Monitor.

Read more about North Korea:

Imprisoned by Kim Jong Il

Will the North fire at South Korean targets?

Decoding North Korea