North Korea’s nuclear extortion drama, the repeated threat of nuclear attack followed by demands for food and financial aid, has exhausted South Korean and Japanese diplomatic patience.

Last year, Japan indicated that North Korea should expect more than expressions of anger the next time it put a ballistic missile on a launch pad in preparation for a test. Pyongyang’s threat theater often starts with erecting a missile and announcing a test flight. Alternatively, Act 1 begins with a nuclear test. North Korea allegedly conducted a nuclear test on January 6.

Weapon range and reliability play a role in Tokyo’s and Seoul’s loss of patience. As Pyongyang’s missile and nuclear warhead technologies improve, the threat to East Asia becomes more immediate. The threat also extends beyond East Asia. The U.S. is considering deploying land-based anti-missile systems in Hawaii (Aegis Ashore). In March 2013, North Korea revealed that Austin, Texas (where South Korea’s Samsung Electronics Co. has a manufacturing facility) is on its target list. North Korea can’t hit Texas … yet.

For Japan, the next time arrived last week when North Korea announced a missile launch. Major Japanese media reported that Defense Minister Gen Nakatani ordered Japan’s military to be prepared “to destroy any missile fired by North Korea that threatens the country.”

This is a message where the messenger matters. For years, Nakatani has argued that Japan must be able to strike enemy military assets preemptively when they threaten imminent attack on Japan. He vigorously advocated changing the Japanese constitution to permit offensive action by Japanese military forces. Last year, Prime Minister Shinzo Abe succeeded in making those changes.

However, when asked to confirm Nakatani’s statement, the defense ministry demurred, arguing confirmation would reveal strategy. A spokeswoman told AFP “… we are taking all possible measures to respond (to a missile launch) by collecting information and coordinating with countries concerned.”

Wiggle room. Diplomats love it. Fuzziness can provide space for compromise agreement. But doubt in an enemy’s mind has military utility, and Nakatani is a leader who would create it and exploit it. Where would Japan’s destruction of a threatening North Korean missile take place? “Fired,” suggests Japan would respond post-launch when the missile is on a track to hit Japanese territory. However, nothing Nakatani said was confirmed or denied. And remember what I said about the messenger.

Say “missile defense.” The first thought is in-flight interception. Japan has previously warned it will intercept North Korean missiles. Japan and the U.S. have anti-missile capable Aegis warships. South Korea is deploying upgraded U.S.-made Patriot PAC-3 anti-missile missiles. Last week, Japan positioned a Patriot PAC-3 launcher in downtown Tokyo, where everyone can see it.

However, destroying a missile on the launch pad is also missile defense. Offensive missile defense may be an oxymoron, but it is an option. A preemptive attack is an act of war. However, repeatedly placing a missile on a pad and threatening to nuke Seoul and Tokyo invites war. A preemptive attack by Japan or South Korea — or even the U.S. — on a North Korean launch site has always been a possibility. But once again, consider the messenger. Has Nakatani introduced the possibility without making it explicit?

How would China react? A North Korean attack — or an attack to forestall a North Korean attack — could ignite a devastating war. Even though they are major trading partners, China and Japan have serious territorial disputes. Nakatani takes a very hard line in those disputes.

Fair bet this wider war would — at a minimum — kill several hundred thousand people. Beijing knows a big war would harm its economy and perhaps erase a decade of growth. An East Asian war could beggar the global economy. Shanghai, Seoul and Tokyo create a lot of value and do a lot of business.

To China’s credit, since 2006, it is increasingly quick to criticize North Korean threat and aggression.

Japan’s loss of patience should tell China that the time has arrived for pre-emptive, coercive diplomacy to permanently change the behavior of North Korea’s murderous regime.

Austin Bay is a syndicated columnist and author.