Autopsy results show Kim Jong-nam, estranged oldest brother of North Korean dictator Kim Jong-un, was killed by a VX nerve agent.

VX is an incredibly deadly chemical weapon banned by multiple international laws and UN resolutions.

Now that it is clear the Democratic People’s Republic of Korea (DPRK) used a banned chemical weapon to assassinate, the United Nations will be forced to act.

Is military intervention all but certain?

World War I started with the assassination of a political figure.

How will the United States respond and, more importantly, whose side will China take?

This potential international crisis started two weeks ago when Kim Jong-nam was assassinated in the terminal of a Malaysian airport.

As the eldest son of Kim Jong-il, Kim spent the first 30 years of his life being groomed to take over command of North Korea upon the death of his father.

That came to an end in 2001, when he was caught attempting to travel to Tokyo Disneyland, using a fake Dominican Republic passport and trying to pass himself off as a Chinese man, Pang Xiong.

His younger brother, Kim Jong-un, became seen as the more stable and reliable choice for succession.

Living in exile in Macau, and drawing on his elite education in Switzerland, a disillusioned Kim became a critic of his own family, calling on North Korea to adopt democratic reforms.

But that all ended Februauy 13, when two women grabben Kim from behind and rubbed a foreign substance in his face.

Confused, and beginning to show the signs of poisoning, he was taken to the airport clinic, but quickly died en route to a hospital.

This was more than a random prank.

Kim was traveling back to Macau under an aliasbeen previously targeted by past North Korean assassination attempts.

Malaysian authorities arrested the two women, both Malaysian, and a North Korean accomplice.

After further investigation, they are searching for four more North Korean suspects.

Kim’s autopsy report shows he died from poisoning by a VX nerve agent.

VX is activated by the mixture of two components.

The United Nations Resolution 687 and the Chemical Weapons Convention banned VX as a weapon of mass destruction.

It is the first proven case of VX being used to kill, and it was used in a clear political assassination.

That is not only a violation of international law against assassinations, it is a violation of international bans on chemical warfare —  meaning if a link back to the North Korean regime is proven, the United Nations will likely take action.

North Korea is already under heavy sanctions, and the actual use of VX in an assassination is a far more serious crime than those committed by Saddam Hussein’s Iraq when the U.N. took military action in 1990.

With a proven chemical weapons program, and a proven intent to use it, North Korea moves from being a future or theoretical threat to national security, to now a proven one.

U.S. allies such as Japan and South Korea will not tolerate a North Korean regime with the ability to carry out chemical warfare and targeted assassinations on their soil, dramatically increasing the odds of military intervention against Pyongyang.

It also places China in a precarious situation.

China is allied with North Korea, partially out of ideology and partially out of necessity.

China also provides tremendous aid to its socialist neighbor to serve as a check on the United States’ presence in South Korea, and to prevent the Kim regime from collapsing, which would lead to dangerous instability on its border with the prospect of 25 million starving and directionless North Koreans flooding into China.

If North Korea refuses to abandon its chemical weapons program, which has already been used in one assassination, China has a decision to make.

Any attempt to overthrow Kim to head off instability and replace him with an allied puppet will likely end in failure.

China’s contributions to North Korea are suppressed in the North Korean media.

North Korea propaganda is highly isolationist and filled with stories of the atrocities committed by the Japanese when Korea was a colony of Japan.

From birth, children are told of North Korean founder Kim Il-sung’s heroic military exploits as an anti-Japanese guerrilla fighter.

Any Chinese-backed regime would be seen as a foreign occupier and colonizer, and would be met with violent insurgent resistance.

That leaves China with two choices, should the situation escalate.

Do they join a military coalition to overthrow Kim, leading to violence, instability, a military crisis on their border, and followed by the establishment of a unified, pro-US Korea on their doorstep?

Or do they stand by North Korea and make it clear any attempt to overthrow Kim will be seen as an attack on a Chinese ally?