Chinese President Xi Jinping’s warning to his American counterpart Joe Biden that “if you play with fire, you will be burned” is the most belligerent rhetoric China has directed towards the United States in decades, perhaps since the United States and the People’s Republic of China established diplomatic relations in 1972.

Why is China so incensed about the visit of Nancy Pelosi, an American Congresswoman visiting Taiwan without the open endorsement of the Biden administration? The answer lies in the details of diplomatic redlines.

US diplomatic relations with China began with the Shanghai Communique of 1972, which states:

The Chinese side reaffirmed its position: the Taiwan question is the crucial question obstructing the normalization of relations between China and the United States; the Government of the People’s Republic of China is the sole legal government of China; Taiwan is a province of China which has long been returned to the motherland; the liberation of Taiwan is China’s internal affair in which no other country has the right to interfere; and all US forces and military installations must be withdrawn from Taiwan. The Chinese Government firmly opposes any activities which aim at the creation of “one China, one Taiwan”, “one China, two governments”, “two Chinas”, an “independent Taiwan” or advocate that “the status of Taiwan remains to be determined.”

The US side declared: The United States acknowledges that all Chinese on either side of the Taiwan Strait maintain there is but one China and that Taiwan is a part of China. The United States Government does not challenge that position. It reaffirms its interest in a peaceful settlement of the Taiwan question by the Chinese themselves.

Then-US President Richard Nixon toasts with Chinese Prime Minister Zhou Enlai at a banquet in Beijing during his official visit on February 21, 1972. Photo: Agencies

In an off-the-record discussion with Asia Times, one of the original members of the Richard Nixon delegation to China in 1972 stated that the Pelosi visit “clearly violates the spirit of the Shanghai Communique.” That stems from the Constitutional status of the Speaker of the House of Representatives.

Suppose that the president or vice-president of the United States was to visit Taiwan. A presidential visit would constitute de facto recognition of a sovereign Taiwan in contravention of the Shanghai Communique because heads of state do not visit heads of state of countries that they do not recognize or plan to recognize.

Diplomatic recognition, after all, was the purpose and the outcome of Nixon’s China visit. A visit by the vice president, the president’s deputy who is elected on the same ballot as the president, would have the same character; one role of the vice president is to stand in for the president on state occasions when the president cannot be present.

Under the Presidential Succession Act of 1947, the Speaker of the House of Representatives is next in line to the vice president for succession. Because of the Speaker’s Constitutional position, she is the third highest official in the United States. A presidential or vice-presidential visit to Taiwan would cross China’s red line. A visit by the Speaker nudges the red line.

The Biden administration’s repeated statements that Pelosi is acting on her own only make matters worse.

In an August 2 interview, Professor Wang Wen of Renmin University was asked by the “Observer” website to comment on the Biden administration’s attempt to distance itself from Pelosi. The news site asked, “Is this [policy] actually stupid, or is the US pretending to be stupid?”

Wen replied: “The United States is acting stupid, but it actually is stupid. This business of pretending to be stupid means they clearly understand China’s fundamental interest and red line on the Taiwan issue, but nonetheless, they have stepped on it repeatedly.”

Military honor guards attend a flag-raising ceremony at the Chiang Kai-shek Memorial Hall in Taipei on March 16, 2018. Photo: Agencies

If President Biden strongly objected to Pelosi’s Taiwan trip, he could have dissuaded her from going. At very least he could have denied her the use of American military aircraft.

After a series of missteps and official corrections, notably including the State Department’s fact sheet on US relations with Taiwan and Biden’s impromptu promise in Japan to defend Taiwan against a mainland military incursion, the Pelosi visit looks to Beijing like an American attempt to blur a red line that for Beijing is a raison d’etre of the Chinese state.  On August 2, China’s Foreign Minister Wang Yi spoke of American “perfidy.”

What the Biden administration has in mind is unclear. Whether by accident or design, it has stumbled into a crisis of the utmost gravity.

Follow David P Goldman on Twitter at @davidpgoldman