U.S-China relations may take a turn for the worse after President-elect Donald Trump publicly insulted the mainland twice in a span of 72 hours. The first incident took place on Friday, when the real-estate billionaire accepted a congratulatory phone call from Taiwan's President Tsai Ing-wen, a move that broke nearly four decades of U.S foreign policy. The 10-minute call with a Taiwanese leader was the first by a U.S. head of state since 1979, when Washington first embraced the "One China" policy under which Beijing views special territories Taiwan, Hong Kong and Macau as part of China. Following the call, Trump tweeted: "The President of Taiwan CALLED ME today to wish me congratulations on winning the Presidency. Thank you!" This post may have further enraged Beijing as mainland media always refer to the Taiwanese head of state as "leader," because the term "president" could imply Taiwan is a separate state. In a subsequent tweet that mocked Washington's long-standing relationship with Taipei, Trump said: "Interesting how the U.S. sells Taiwan billions of dollars of military equipment but I should not accept a congratulatory call." China's Foreign Ministry has lodged a diplomatic complaint with U.S. officials, warning that the One China principle was the political basis of bilateral ties, Reuters reported Saturday.

An employee shows a mask of American president-elect Donald Trump at a latex crafts factory on November 9, 2016 in Shenzhen, Guangdong province of China. Li Jianqiang / VCG / Getty Images

Late on Sunday, Trump then accused Beijing of manipulating its currency, unfairly taxing U.S. products and militarizing the South China Sea — also via Twitter. Because his transition team has yet to announce clear policy declarations, the Republican's actions — including tweets and choice of advisers — are being closely watched by a world still trying to figure out the global implications of a Trump administration. "Trump railing against China on Twitter like it is a Celebrity Apprentice feud is not funny, but deeply, deeply worrying for the world," U.K. Labor politician Ed Milliband tweeted on Sunday.

Friday's phone call

Strategists' views on the call with Tsai are mixed: It could be a calculated shift in U.S. foreign policy, a geopolitical game, or simply a rookie mistake.

"Trump's Asia team is broadly hawkish on China and in favor of defending democratic Taiwan on ideological grounds, so the phone call could have been a deliberate signal about a looming policy shift," said Ashley Townshend, research fellow at University of Sydney. The president-elect's advisers include many who are openly critical of the mainland, including author Mike Pillsbury and academic Peter Navarro. Others think the phone call may be an intentional move in the game of geopolitics. "This can be understood as part of a signaling game — a shot across the bow — of how Trump will deal with China," said Eduardo Araral, vice dean of research and associate professor at the National University of Singapore. "Trump is basically telling China he will play hardball. This is a predictable gambit for negotiators — to tell the other party that you are a tough negotiator."



Or America's next president — who reportedly shunned intelligence briefings in the weeks after his election victory — may have simply acted too rashly.

"It's also possible that Trump simply took the call on his advisers' recommendations, without fully appreciating the diplomatic consequences," Townshend said. Kellyanne Conway, the president-elect's senior adviser, told Fox News on Sunday that Trump was routinely briefed by "credible sources" on international intelligence and was "fully aware of the One China policy." But whatever the reasoning, the mixed messages behind the chat with Tsai are sure to have hefty consequences for U.S. policy in Asia. "If Taiwan thinks it has more American support that it actually does, it might take provocative steps towards Beijing that risk a crisis," Townshend said. "Similarly, if Beijing thinks that Trump's phone call was a rookie error, when it was actually intended to be signal about stronger U.S. policy on Taiwan, the U.S. and China could be on a diplomatic collision course."

Sunday's tweets