Donna Leinwand Leger

USA TODAY

In a few sentences on Sunday, President-elect Donald Trump upset an apple cart precariously balanced for 37 years across the Taiwan Strait.

Trump said in an interview with Fox News that he did not feel "bound by a one-China policy," prompting the communist government in Beijing to voice its "serious concern" on Monday that Trump could take steps to change U.S. policy toward China and the self-governing island of Taiwan.

His comments came nine days after a telephone call with the president of Taiwan that broke with U.S. policy, which bars such direct communication, and upset the Beijing leadership.

The U.S. recognition of a "one-China" policy stems from 1979, when the U.S. switched diplomatic recognition from Taiwan to the People's Republic of China (PRC).

In the 1979 U.S.-P.R.C. Joint Communique, the United States recognized the communist leadership in Beijing as the sole legal government of China, acknowledging the Chinese position that there is one China and Taiwan is a breakaway province that is part of China.

"The Taiwan question bears on China's sovereignty and territorial integrity and touches our core interests," Chinese foreign ministry spokesman Geng Shuang said. "Adherence to the one China principle serves as the political foundation for the development of China-U.S. ties. If this foundation is wobbled and weakened, then there is no possibility for the two countries to grow their relations in a sound and steady way and cooperate on key areas."

Officially, the U.S. government does not support independence for Taiwan, now a democracy that elects its own president and parliament.

U.S. relations with the island are governed by the 1979 Taiwan Relations Act, which outlines the U.S. commitment to help Taiwan maintain its military defense. Last year, the U.S. approved $1.8 billion in arms sales to Taipei.

Taiwan: Trump call was not China 'policy shift'

Washington maintains unofficial relations with Taiwan through the American Institute in Taiwan (AIT), a de facto embassy that implements U.S. policy, facilitates trade and issues visas. Taiwan maintains a de facto embassy in Washington, D.C., through its Taipei Economic and Cultural Representative Office (TECRO).

Trade between the U.S. and Taiwan is robust: The U.S. is Taiwan's second-largest trading partner and Taiwan ranks as the ninth-largest trading partner for the U.S. According to the State Department, companies from Taiwan employ more than 12,000 workers in the United States.

For Taiwan, the lack of diplomatic recognition by the U.S. and most other nations means that it cannot belong to international organizations, such as the United Nations, that require statehood as a condition of membership. Its president, Tsai Ing-wen, cannot make official visits to the U.S. and has not been invited as an official delegate to U.S. events, such as presidential inaugurations.