Trump’s Taiwan Play: The phone call with the island’s president looks like a calculated move.

Dec. 4, 2016   Americans had to get used to Donald Trump breaking all the rules of presidential taiwancampaigning, and it looks like the world will have to adjust to a President Trump who will also violate diplomatic convention. One early lesson is not to overreact to every break with State Department protocol as if it’s the start of World War III.

The U.S. media had their 19th nervous breakdown Friday after the Trump transition said the President-elect had taken a congratulatory call from Taiwan President Tsai Ing-wen. Mr. Trump also later tweeted that he had spoken to “the President of Taiwan.” Doesn’t he understand this simply isn’t done? No American President or President-elect has talked to a Taiwanese President since 1979, and this violation of tradition is being portrayed as a careless, bone-headed provocation to Beijing.

Well, maybe it was calculated—and perhaps even useful. Trump Asia adviser Peter Navarro has advocated cabinet-level visits to Taiwan and an end to the U.S. bow to Beijing’s “one China” policy, which insists that Taiwan is part of China and shouldn’t be treated as an independent state. Perhaps that goes too far, but it is past time for the U.S. to recalibrate its Taiwan policy.

Ned Price, spokesman at the Obama National Security Council, suggested that Mr. Trump made a mistake, saying the U.S. remains “firmly committed to our ‘one China’ policy based on the three Joint Communiqués and the Taiwan Relations Act.” But the communiqués from the 1970s and ’80s do not say that the U.S. supports Beijing’s view of “one China,” only that the U.S. acknowledges that both China and Taiwan agree on that principle. That is a crucial distinction.

Taiwan and the world have also changed since those communiqués. Taiwan has become a prosperous and democratic polity integrated into the world economy. Most Taiwanese now want to maintain their de facto independence. They resent Beijing’s bullying to force their leaders to move toward reunification.

Previous U.S. Presidents have eased restrictions on contact with Taiwanese officials to reflect this reality. Bill Clinton let President Lee Teng-hui give a speech at Cornell University in 1995. George W. Bush allowed President Chen Shui-bian to visit the U.S. in transit to countries in Latin America that maintain diplomatic relations with Taiwan.

The U.S. is obligated to assist the self-governing territory in defending itself under the 1979 Taiwan Relations Act, and every Administration since has sold weapons to Taiwan. Mr. Clinton sent a U.S. carrier through the Taiwan Strait in 1996 when China was especially threatening.

Previous Taiwanese leaders tried to exploit U.S. support to push for a formal declaration of independence, which Beijing warns would be cause for war. Mr. Trump has to be careful not to encourage Ms. Tsai, who has advocated for independence in the past, to make the same mistake. But Ms. Tsai has studiously avoided such declarations since her election earlier this year, and she has been careful to say she wants good relations with Beijing despite China’s attempt to isolate her.

Mr. Trump shouldn’t concede Beijing’s power to intimidate the world’s democracies into isolating Taiwan. The U.S. has an interest in supporting Taiwan as a model for China’s future development. And adapting Taiwan policy could benefit the wider U.S.-China relationship.

Beijing says denying sovereignty for Taiwan is a core interest. But the U.S. has a core interest in preventing North Korea from threatening the world with nuclear-armed missiles. The rest of Asia has a core interest in preventing China from unilaterally asserting its dominance over the East and South China Seas. Respect for core interests goes both ways.

It’s notable that China has reacted better than the U.S. media to Mr. Trump’s phone conversation. Beijing protested but its Foreign Minister dismissed it as a “petty trick” by Ms. Tsai. Beijing censored the news inside China, while the English-language China Daily suggested Mr. Trump simply made a mistake.

President Obama had no success convincing China to rein in Pyongyang, and Chinese officials walked all over him on his first visit in 2009. Mr. Trump’s tougher stance may prove to be a better opening move in the deal-making to come.