Republican US presidential candidate Donald Trump speaks at his New York presidential primary night rally in Manhattan, New York, US, April 19, 2016. [Photo/Agencies]

Now it's certain: We stand on the precipice of a bloody and historic battle. No, not a war between China and the US, who will continue to be the best of frenemies (friends and enemies）muddling through because there is no alternative. Rather momentarily a nasty, savage battle strewn with body parts between the now all-but anointed US Presidential candidates Hillary Clinton and Donald Trump begins. The outcome, however, is far from clear as is the fallout for China in this brave new world.

This will be a war full of skeletons. Trump has said that he has no interest in Clinton's plan for the future, and that he will instead concentrate on her past—the skeletons in her closet. So we can expect him to not only follow Senator Bernie Sanders' playbook accusing her of being the candidate of the 1%, but also harping on her record as Secretary of State and First Lady. And for good measure, Bill Clinton's sexual misadventures will be luridly revisited, sparking a retaliatory review of Trump's own sexual escapades, ones that he even proudly boasts about.

But of much more consequence are Trump's alleged ties to the Mafia and a cast of unsavory characters, as well as Trump's dubious record of success as a businessman. And of course, all the outrageous remarks Trump has made will be replayed ad infinitum by the Democrats.

This will be a battle of blood. Trump started it off in his inimitable juvenile manner, picking a fight with a female FOX-TV journalist who he said had "blood coming out of her whatever". More substantively, he will focus on the death of the American ambassador in Libya and blame his opponent for her flawed leadership. Both candidates will discuss the bloodshed around the world recently by the Islamic State and other terrorists and non-terrorist actors.

This will also be a contest for hearts and minds, indeed for the soul of the Republican Party. The "Party of Lincoln" began idealistically as a high-minded group opposed to slavery but now it has descended into a selfish, backward-looking, isolationist bunch of know-nothings. Abraham Lincoln must indeed be spinning in his grave.

The election will determine if the Republicans will get back to a model of pragmatic cooperation to govern, or will remain in opposition, especially if Trump leads the party to a devastating defeat of historic proportions such as conservative Barry Goldwater's in 1964. One thing is certain however, Ted Cruz is far from dead, and this talented but dangerous demagogue could well be back with his extremist views in 2020.

The Democrats will be pursuing its traditional liberal agenda but will questioning free-trade, one of the pillars of the international economic order that has stimulated the world economy since the end of World War II.

What does it mean for China? It's hard to say as China-bashing by candidates is as much as pastime in US presidential elections as kissing babies, usually superseded by sanity and pragmatism after the inauguration.

The choice for China in this case, however, may well be between the devil and the deep blue sea. Trump seems hell-bent on starting a destructive trade war with China, among others. Clinton, author of the US pivot/rebalance to Asia, is no friend of China's.

In either case, China, a country through its long history has admired negotiating through strength, will see a switch from Barack Obama's softball to a newly intense hardball contest. At least Clinton is the devil we know and at least we have many established bilateral dialogues to keep us talking and minimizing the chance of something more ominous.

No matter who wins, the election's outcome will be of historic proportions. Either a true political outsider will be elected by legions of angry disaffected voters, armed with a blank slate and the possibility that anything goes, or a woman of considerable experience but disliked by many, will become President of the United States for the first time in its 240-year history.

The author is a senior adviser to Tsinghua University and former director and vice-president of ABC Television in New York.