US President-elect Donald Trump speaks during a news conference in the lobby of Trump Tower in Manhattan, New York City, US, January 11, 2017. [Photo/Agencies]

When it comes to tolerance, it is our tradition to display a big heart. That is why one can normally get away with making the same mistake twice, as one will be given the benefit of the doubt.

But one will seldom be given the benefit of the doubt twice, because doing the same wrong for a third time shows intent.

When United States president-elect Donald Trump broke his country's longstanding diplomatic protocol and answered a "congratulatory call" from Taiwan leader Tsai Ing-wen, the Chinese foreign minister merely responded by calling it a "petty trick" by Taipei.

When, just nine days later, Trump told Fox News Sunday the US would not "be bound by the one-China policy", Beijing simply reiterated that acknowledgment of one China is fundamental, and non-negotiable, for healthy ties.

To many, that was a mistake Trump made twice.

Yet when Trump told the Wall Street Journal on Sunday "Everything is under negotiation including one China," reinforcing the impression that he intends to use Taiwan as a bargaining chip, Beijing did not go beyond what it had already said.

Such a measured response can only come from a genuine, sincere wish that the less-than-desirable, yet by-and-large manageable, big picture of China-US relations will not be derailed before Trump even enters office.

It would be a blessing for both parties, and indeed for the world, if such goodwill could be appreciated and reciprocated. But that seems unlikely.

It seems wishful thinking to assume Trump and his team's remarks on Taiwan have been based on bluster or miscalculation. On the contrary, it appears the next administration is intending to use the one-China policy as its trump card.

Taiwan has been off limits in China-US diplomacy thanks to the understanding that it is a Pandora's box of lethal potential, and that opening it may upend the hard-earned, firmly held fundamentals governing the relationship.

If Trump is determined to use this gambit on taking office, a period of fierce, damaging interactions will be unavoidable, as Beijing will have no choice but to take off the gloves.

It would be good if after his inauguration Trump can demonstrate more statesmanship. But Beijing should not count on his raising the stakes being a pre-inauguration bluff, and instead be prepared for him to continue backing this bet.

It may be costly. But it will prove a worthy price to pay to make the next US president aware of the special sensitivity, and serious consequences of his Taiwan game.