Republicans rallied around Donald Trump on Saturdary after he reversed four decades of American policy toward China with a call to Tsai Ing-wen, the Taiwanese president.

The US does not officially recognise Taiwan’s sovereignty, and Beijing lodged a formal complaint over the call, the first such communication with a Taiwanese leader since 1979.

But the president-elect won the praise of prominent figures within his party for declining to bow to diplomatic norms.

Ted Cruz, the Texas senator who was Mr Trump’s fiercest rival during the primary elections, called the decision an “improvement” over President Barack Obama’s foreign policy.

I would much rather have Donald Trump talking to President Tsai than to Cuba’s Raul Castro or Iran’s Hasan Rouhani. This is an improvement.

Tom Cotton, the Arkansas senator who serves on the armed services committee, was more forthright in his praise: “I commend President-elect Trump for his conversation with President Tsai Ing-wen, which reaffirms our commitment to the only democracy on Chinese soil,” he said in a statement.

Pete King, the hawkish Republican congressman, concurred.

“Plaudits to President-elect Trump for his historic phone call to Taiwan President Tsai Ing-wen. Strong message to China. New day in Asia,” he wrote on Twitter.

But while some lauded what they saw as an historic achievement, others sought to downplay the conversation.

Donald Trump

“It’s not policy, it’s a phone call,” Mark Meadows, another Republican Congressman, told the Hill newspaper.

That was certainly the hope in China, with the country’s foreign minister referring to the call as a Taiwanese “trick”.

Mr Trump did not signal whether he plans to further upend US-China relations, but he did contradict reports from Taiwan that he had initiated the call.

The President of Taiwan CALLED ME today to wish me congratulations on winning the Presidency. Thank you!

Interesting how the U.S. sells Taiwan billions of dollars of military equipment but I should not accept a congratulatory call.

Ari Fleischer, the former press secretary to George W Bush, expressed alarm after the call, saying he “wasn’t even allowed to refer to the government ‘of’ Taiwan” during his time in the White House, but was instead instructed to say government “on” Taiwan.

“So long as Trump called knowing it would change the status quo, I’m fine with it,” he said. “I hope it was by design.”

The consensus among many Democrats was that Mr Trump did not understand the ramifications of his calls to the president of Taiwan, as well as the leaders of Pakistan and the Philippines.

Chris Murphy, the Connecticut senator, said Mr Trump’s “radical temporary deviations” from established US policies would weaken America’s alliances and could lead to war.

Donald Trump reportedly invited Rodrigo Duterte, president of the Philippines, to Washington CREDIT: EUGENE HOSHIKO/AP

“What has happened in the last 48 hours is not a shift,” he said. “These are major pivots in foreign policy without any plan. That’s how wars start.”

Before the call with Ms Tsai, Mr Trump spoke with Nawaz Sharif, the prime minister of Pakistan.

He praised Mr Sharif profusely and appeared to accept an invitation to visit Pakistan, ruffling feathers in India.

The president-elect also spoke with President Rodrigo Duterte of the Philippines, who has called Mr Obama a “son of a whore”.

According to a spokesman for Mr Duterte, Mr Trump invited him to the White House next year and praised his violent anti-drug campaign, which has claimed more than 1,000 lives.