Chinese President Xi Jinping's stark warning to Donald Trump regarding Taiwan sharpens distinctions between ultimatums. However, increasing non-negotiable positions limits diplomatic space and heightens the risk of accidental conflict.

<p>Chinese President Xi Jinping’s blunt warning to US President Donald Trump about Taiwan was clearly intended to sharpen the distinction between this ultimatum and the many others Xi has issued. But expanding the number of non-negotiable positions reduces the space for effective diplomacy and raises the risk of accidental conflict.</p>