So how did the Korean War start? Was it that America was rattling its sabers? There is a view among historians that the fatal error was the opposite. It occurred when the President Truman’s state secretary, Dean Acheson, spoke about the defense of Japan. “I can assure you that there is no intention of any sort of abandoning or weakening the defenses of Japan, and that whatever arrangements are to be made, either through permanent settlement or otherwise, that defense must and shall be maintained,” the secretary said in remarks at the National Press Club. “This defensive perimeter runs along the Aleutians to Japan and then goes to the Ryukyus. We hold important defense positions in the Ryukyu Islands, and those we will continue to hold.”

Ooops. Seems the secretary forgot — or didn’t intend — to mention Korea, which the Soviet party boss, Joseph Stalin, and his camarilla immediately interpreted as a green light to attack. It would be inaccurate and wrong to blame the 33,686 battle deaths of American GIs and the millions of other military and civilian deaths in the Korean War on Acheson. Responsibility for those deaths belongs solely to the Communists, in Korea, China, and the Soviet. But it would not be inaccurate to reflect on Acheson’s blunder in the wake of the hash that President Obama and his own camarilla are making of the pivot to Asia.

The latest blunder is signaled on the front page of the London Financial Times, under the headline: “Biden fails to back Japan on call to scrap China’s new air defense zone.” It seems, according to the FT, that Mr. Biden, in Tokyo at the beginning of his Asian tour, was trying to reassure Japan in that America would defend Japan from, as the FT put it, “an increasingly assertive” Communist China, which has declared an air defense zone in the East China Sea. “But even as he reiterated that the US was ‘deeply concerned’ that China’s declaration of a wide air defense identification zone late last month risked ‘accidents and miscalculations,’ he did not back Japan’s call for scrapping it.”

So what does one figure the Chinese Reds are going to make of that? On the op-ed page of the FT, columnist Martin Wolf compares the situation to the testing of British and French resolve that was launched in the early 20th Century by the Kaiser in Germany. History teaches, he writes, that “frictions between status quo and revisionist powers may well lead to conflict, however ruinous the consequences.” He thinks the Chinese party boss, Xi Jinping, should “think again — and halt.” But what incentive is the waffling of Mr. Biden giving them to do so — particularly when our whole pivot to Asia is born of a retreat in the Middle East and is being implemented by a secretaries of state and defense who turned against, in Vietnam, the last war we were in with the Chinese communists? The lesson of the Korean War is that hostilities can be invited by weakness and indecisiveness and that it can be signaled over a few rocks between China and an ocean trench named Ryukyu.