The Kang Nam is an aging, rusty cargo ship that has passed through numerous owners. Now flying the flag of North Korea and chugging slowly through East Asian waters toward the Strait of Malacca, it is an unlikely possible flash point for international tensions.
"North Korea has a path toward rejoining the international community, and we hope they take that path," said Mr. Obama on Monday in a prerecorded interview on CBS. "What we're not going to do is to reward belligerence and provocation in the way that's been done in the past."
Tensions have been running high on the Korean peninsula since the May 2 underground nuclear explosion. Pyongyang has said it will consider any attempt to intercept the Kang Nam to be an act of war.
Low-tech weapons on board?
The Kang Nam's destination most likely is Myanmar – possibly the port city of Thilawa. Its cargo is probably low tech but still dangerous: artillery, rifles, and other conventional arms.
According to South Korean media reports, the Kang Nam itself was probably built in Germany in the late 1980s. It then passed through a series of owners to a South Korean maritime firm, which in turn sold it to the North.
A series of Kang Nam ships are in Pyongyang's possession, named Kang Nam 1 through Kang Nam 5. The Kang Nam 1 is the ship being shadowed by the Aegis missile destroyer USS John McCain, named for the senator's father and grandfather.
It is not fast. It is making about 10 knots as it crawls down the Chinese coast, according to South Korean media.
How long before the Kang Nam needs fuel?
A key question is whether the ship can make it to Myanmar without refueling. US officials have said that they do not know how fuel-efficient the Kang Nam is or how much fuel it carries.
Singapore is perhaps the largest maritime service and refueling stop in the world, situated as it is at a crossroads of the Indian Ocean. It has said it would act "appropriately" if the Kang Nam calls.
The new UN Security Council resolution calls for ports to withhold fuel and supplies from ships thought to be carrying prohibited items, unless those ships allow themselves to be searched.
"Singapore does not want to be thought of as a contributor to the illicit weapons trade," says Mr. Schoff.
It is possible that the next act in the drama could be a standoff, as a North Korean captain refuses to allow port authorities to board his vessel, and they in turn refuse him the fuel to proceed to his destination.
It is also possible that the USS John McCain may intercept the Kang Nam before it arrives at any port. US officers would seek permission to board – which would almost certainly be denied.
In that case, the US warship is supposed to direct the intercepted ship to a nearby port, under terms of the UN resolution. But the resolution does not authorize use of force to carry out its provisions.