Important, even vital, American national interests as well as global peace and stability are at stake in how – indeed, whether – President-elect Donald Trump understands the underlying principles of the United States’ long-standing “one-China” policy and the mutual commitments involved in the normalisation of relations with the People’s Republic of China.

On the face of it, the president-elect seems to believe that, having identified an issue of great importance to Beijing (“one China”), he can leverage Chinese cooperation on issues of importance to Washington by suggesting he is willing to forego continued cooperation on that critical Chinese interest.

As a person who has engaged in give-and-take behaviour throughout his business career, one can understand Trump’s attraction to identifying and utilising points of leverage. But even though Trump says he understands the one-China policy, in fact it is critical to distinguish it, and its grounding in matters of Chinese sovereignty, from a commercial deal. The latter are open to haggling; the former is not.

Although the US recognises the government of the PRC as the “sole legal government of China” and maintains no official relations with Taiwan, it does not “accept” Beijing’s position that there is “one China” of which Taiwan is a part. Washington does acknowledge that position, has said it would not challenge it, and (in a 1982 US-PRC communiqué under President Reagan) has committed itself not to pursue a policy of “two Chinas” or “one China, one Taiwan”.

But other than underscoring the importance of not using or threatening the use of force or coercion, Washington has not taken a stance on what the ultimate cross-strait relationship should be. That is a matter for the people on the two sides to determine, peacefully and willingly. Meanwhile, under the terms of the 1979 Taiwan Relations Act, the US maintains robust “unofficial” relations with Taiwan. These are key elements of what the US calls its one-China policy.

Watch: China warns Trump on Taiwan comments

In return, though not foreswearing the use of force if Taiwan pursues independence or unalterably blocks unification, China has committed itself to a “fundamental policy” of “peaceful reunification”.

While far from ideal for the US or Taiwan, the resultant arrangements have supported the remarkable political, economic and security developments in Taiwan that have so impressed people in the region and around the world. By seeming to place the US’ one-China policy on the auction block, Trump has not only put all of that at potential risk, he has put in danger a range of American interests where either active cooperation with Beijing is essential or at least management of differences is required.

Beijing says interference with one-China principle would ‘seriously’ impact on peace

One can quibble over whether Trump is right in all of his choices regarding issues where he seeks greater cooperation from China. (Many economists say that Chinese currency manipulation is an issue perhaps a decade out of date.) But he is right that there are several critical problems, including North Korea’s nuclear programme, where he needs Beijing to step up to the plate to avoid strategic crises.

But clearly those issues are complicated and not susceptible to simple solutions. Otherwise they would have been resolved long ago. Recently, though not retreating from the promotion of China’s interests, President Xi Jinping (習近平) has made clear he does not want a confrontation with the US but, rather, to cooperate where possible and carefully manage issues where the two sides differ.

Indeed, the irony of Trump’s implicit threat to abandon the one-China policy is that he would undermine such cooperation and likely raise the threat level in areas such as the South China Sea.

One might also note that, while the government in Taipei was quite pleased at having broken through a barrier by arranging an unprecedented telephone call between President Tsai Ing-wen and President-elect Trump, it has gone silent since Trump raised the issue of not being “bound” by the one-China policy.

Taiwan’s security is intimately tied up with a willingness to forego any hint of an independence policy. And while Tsai has been careful not to cross any red lines in this regard, the current tenuous state of cross-strait relations is due to her unwillingness to go further and openly embrace “one China” or forswear independence. For the US to suggest it might support separate status for Taiwan by dumping the one-China policy is not only disturbing but profoundly dangerous for the island. At a minimum, if Trump actually proceeded along the lines hinted, Taipei would come under much more severe pressure to abandon its reserved position and fully meet Beijing’s demands.

How a snub of the one-China policy almost led Beijing and US into war in the 1990s

Perhaps Trump was not suggesting abandoning the one-China policy but merely questioning the protocols and conventions that have grown up around it. Limits have applied to high-level visits between Taiwan and the US and to the conduct of meetings between the two sides. Depending on the specifics, even playing around with those limits could have substantial costs. But, if Trump is genuinely willing to toss aside the basic one-China policy, or seriously views it as a bargaining chip, that would have far-reaching consequences.

Many observers suggest that China can’t afford to break relations with the US. Perhaps not. But there are many areas including economic ties – presumably of some importance to the president-elect – as well as strategically important relations, where challenging China on such a basic – as China would say, “core” – interest would inevitably have major consequences.

A former US State Department official, Alan Romberg is the Director of the East Asia programme at Washington think tank Stimson Centre