Fictional plots involving the White House abound. But nothing has prepared the world for the live drama that has engulfed the most powerful office on the planet. The news that President Donald Trump and his wife have tested positive for Covid-19 a month before his bid for re-election has plunged the country’s leadership into uncertainty, upended the election campaign and rattled financial markets. It raises concerns Trump will escalate tension with China by ramping up blame for spreading the virus, or the “China plague” as he referred to it in the first campaign debate. He can no longer shift the focus from his mismanagement of a pandemic that has killed more than 200,000 Americans. He will have to contend with continuing attacks for having persistently played down the severity of the virus and publicly spurning face masks and social distancing as he held campaign rallies that attracted thousands. The diagnosis followed news that one of his closest aides had tested positive. It is unclear if Trump has infected other aides or Vice-President Mike Pence. If the president can catch Covid-19 anyone can. Other world leaders already have, including Britain’s Boris Johnson who became critically ill. Trump has cancelled important election rallies. Doctors say he is well enough to campaign from isolation in the White House against Democratic Party challenger Joe Biden. But his age, 74, looms over hopes that he will remain asymptomatic and free of serious after-effects. This highlights the constitutional role of Pence, his successor in the event of incapacity. Trump will lose much of his remaining time on the campaign trail, where he is most comfortable with his core support. If he becomes sick it will even raise questions about postponing the election, or his place on the ballot. In any case the positive test could devastate his political fortunes after months of playing down a pandemic as it killed many hundreds of his countrymen and women every day. Biden is not thought to be at heightened risk of infection after the debate with Trump on Wednesday, because organisers ensured exemplary social distancing. But what if he too becomes infected? If Trump emerges unscathed, will he spin it as vindication of his reckless disregard for science? How will that affect the election result? Or if he gets really sick, what will it mean for the US and the world? His infection raises endless short- and long-term questions. When on the defensive, Trump only knows offence. So he is seen as likely to seize the opportunity to redouble his attacks against China and ramp up pressure. Despite the US-China trade war, China may not have been the focal point of the first presidential debate, but it will not surprise if that changes dramatically, making it a centrepiece of the campaign and relations with the US even more problematic.