The assassination of North Korean supreme leader Kim Jong Un's half brother Kim Jong Nam in Kuala Lumpur last month kicked over a hornet's nest. Diplomats have been zipping everywhere with threats, recriminations and denials. Pyongyang's testing of multiple ballistic missiles March 6 that splashed down in Japan's exclusive economic zone did precious little to alleviate international concerns. Among the more significant reactions buzzing about is the United States' review of North Korea's rumored involvement in the assassination — and whether this act justifies placing it back on the list of state sponsors of terrorism.

While finding itself on the list for the first time since 2008 would be painful, the sting would pale in comparison to the deep wound China inflicted upon Pyongyang when it announced it will not be buying coal from the country for the remainder of the year. Pyongyang is overtly reliant on coal exports to fuel its economy and finance its $800 million negative trade balance, and China buys 90 percent of the North's exports.

Of course, China's move wasn't quite so straightforward: Before issuing the ban, Beijing openly breached U.N. caps on monthly coal imports and bought almost 2 million metric tons (worth $188 million), providing Kim with a much-needed cash infusion. For the record, according to the latest round of sanctions, the North is allowed to export just $400 million worth of coal a year.