Ming Dao, a 57-year-old Chinese-American who came to the US almost 30 years ago, is a recent convert to Donald Trump’s campaign. Over the past two years, he has started at least 10 social-messaging groups with names such as “Americans for President Trump” to reach fellow Chinese-American voters.

But these groups could disappear at any moment: they are all on WeChat, the Chinese social app that Mr Trump has threatened to ban in the US.

While most Chinese-Americans voted for Hillary Clinton in the 2016 election, four years later the loudest voices on WeChat are pro-Trump. The partisan blogs on WeChat with the most reach are Republican leaning, according to research by Chi Zhang with Columbia’s Graduate School of Journalism, who describes the platform as “asymmetrically polarised”.