By Dick Morris and Eileen McGann

When the Japanese military invaded Manchuria in the early 1930s, Hitler, Mussolini and Japan’s own government watched nervously to see what the League of Nations and the Western powers would do. Now it is North Korea and Iran who are watching and wondering.

If the United Nations, and the powers it represents, is as impotent as was the League in the 1930s, it will send the same signal to other would-be proliferators: that the rest of the world will sit by and do nothing. By so blatantly flouting international opinion and U.N. resolutions, North Korea has essentially said to the rest of the world: “Put up or shut up.”

The irony, of course, is that North Korea is probably the single state in the world most vulnerable to international sanctions. It produces no energy of its own. If China chose to bring the country to its knees, it could do so in a heartbeat. But will it?

China is worried about triggering a flood of North Korean refugees across its borders and tends to be protective of its erstwhile ally.

But the real pressure point on China is Japan. If the Japanese signal that they will respond to the North Korean nuclear test with a decision to change their constitution and develop nuclear weapons themselves, the impact on both China and North Korea will be immense.

But the most important actor is, of course, President Obama. It is really he who is being tested. If he simply settles for ineffectual sanctions or a round of international condemnation, he will be showing a weakness that virtually invites exploitation by the rest of the world. If he only pursues diplomatic negotiations without economic or military clout behind them, the other aggressors — the latter-day Hitlers and Tojos — will draw their own conclusions.

And what will be the tone and the role of the new secretary of State, Hillary ClintonHillary Diane Rodham ClintonFarrow: Clinton staff raised concerns over Weinstein reporting Perry says Trump directed him to discuss Ukraine with Giuliani: report The Memo: Once the front-runner, Biden now vulnerable MORE? Peter Rodman, former aide to Kissinger, wrote in his splendid book Presidential Command that the Department of State “can rarely ever bring itself to admit that diplomacy is not working; in its mind, diplomacy is perpetually deserving of ‘one more chance.’ Sometimes this seems to degenerate into dialogue for its own sake, without regard to results or strategy or even the leverage that might make dialogue more fruitful.”

If Hillary meekly goes along with an Obama policy of accommodation, she will lose forever her ability to portray herself as a national security hawk — a crucial step for any woman running for president.

In Israel, Benjamin Netanyahu will also be watching to see how Obama and Clinton react. He will want to know if there is any starch behind America’s demand that Iran stop its own progress toward the bomb. If the Obama Administration folds, he will know that he must depend on his own military to act, even in the face of global anger, since the United States will be paralyzed as long as Obama is at the helm.

Just as the key question for Bush was when he would resort to diplomacy, given his reputation for war, so the real issue with Obama is when will he fight, given his penchant for negotiation.

In the case of North Korea, of course, military action is off the table since it already has the bomb. But if the United States stiffens Japanese and Chinese resolve and takes the lead, there is no doubt that economic sanctions — real sanctions that include energy — would bring North Korea to its knees quickly.

The whole wide world is watching.