In what must be one of the fastest diplomatic negotiations in U.S. history, President Trump suddenly reversed course and embraced the long-standing “One China” policy recognizing mainland China as that country’s sole legitimate government.

The sudden concession came during a long telephone call between Trump and China’s President Xi Jinping Thursday night, Friday in Asia. The official White House account of the conversation said: “The two leaders discussed numerous topics and President Trump agreed, at the request of President Xi, to honor our ‘one China’ policy.” Boom!

As the Chinese say, That was easy. Elsewhere, the administration described their first contact as “extremely cordial.” It said the two leaders exchanged reciprocal invitations for official visits and concluded optimistically: “President Trump and President Xi look forward to further talks with very successful outcomes.” The complete 108-word text is below.

After his November election Trump took a congratulatory call from Taiwan’s President Tsai Ing-wen, the first time a president or president-elect had spoken to that government in 38 years. It was an unexpected de facto recognition of Taiwan and a breach of protocol that roiled the arcane world of Asian diplomacy. During the ensuing uproar, one of many since Nov. 8, deal-maker Trump said, “Everything is under negotiation, including ‘One China.'”

During the long presidential nomination and election campaigns, Trump sounded like a new sheriff riding into town. He made much of how outrageously China had taken advantage of the United States and its inept leadership, especially involving currency manipulations and lop-sided trade deals that always benefited China to the U.S. detriment.

Trump even threatened the use of tariffs on Chinese goods, which historically prompt retaliatory levies to no one’s ultimate benefit. Trump has expressed a strongly nationalistic trade stance, in direct opposition to traditional Republican free-trade positions in place since World War II. He’s already withdrawn from the Trans-Pacific Trade Partnership.

Like virtually everything Trump says, the presidential candidate’s statements raised loud cries of concern, some of them genuine. They suggested he would ignite a trade war with major partners such as China, an authoritarian regime that has its own brand of economic nationalism. Trump responded, “We already have a trade war. And we’re losing badly.”

Trump’s sudden agreement with China’s leader will encourage many worried about opening frictions with the world’s most populous nation.

The quick shedding of oft-repeated stridency toward China could also demonstrate a powerful pragmatism by the political rookie, an indication he has an eye on other priorities such as China’s unilateral island-building in the South China Sea.

Trump has often spoken admiringly of the power of unpredictability, saying the country needs more of it in foreign policies. Unpredictability may keep competitors off-balance in politics or real estate, but allies tend to prefer steady and reliable. Witness allied hand-wringing over conflicting Trump statements on NATO. Trump will have an opportunity to demonstrate steady in meetings today with Japan’s Prime Minister Shinzo Abe and in their joint news conference.

The official White House account of the conversation with the Chinese leader follows:

President Donald J. Trump and President Xi Jinping of China had a lengthy telephone conversation on Thursday evening. The two leaders discussed numerous topics and President Trump agreed, at the request of President Xi, to honor our “one China” policy.  Representatives of the United States and China will engage in discussions and negotiations on various issues of mutual interest.

The phone call between President Trump and President Xi was extremely cordial, and both leaders extended best wishes to the people of each other’s countries.  They also extended invitations to meet in their respective countries.  President Trump and President Xi look forward to further talks with very successful outcomes.