Seizing upon China's recent economic turbulence like sharks that have smelled blood, hypo-critical Republican presidential candidates are circling President Xi Jinping's state visit to the US this month, making a successful negotiation with US President Barack Obama less likely.

But for China's recent economic setbacks, these demagogues would still be tripping over each other in a race to the bottom on the immigration issue led by the buffoon in a bouffant. They call to mind what a disgraced US vice-president (Spiro Agnew) of a disgraced president (Richard Nixon) once said: a bunch of "nattering nabobs of negativism".

Former presidential candidate and ambassador to China, Jon Huntsman, rightly described our countries being in "the most complex and challenging relationship of the 21st century".We are the best of "frenemies" and will remain so. However, unlike all the already contentious bilateral issues, such as cyberspying, island disputes and human rights, for which expectations for progress are limited, the economic events of recent weeks do present added impetus to one item on the agenda whose negotiation has bogged down, and should and can be resuscitated: the Bilateral Investment Treaty.