Since then, Su has signed up for more than 200 WeChat groups and become a key organiser of a nationwide Chinese American movement supporting Republican presidential candidate Donald Trump. WeChat has been integral to her political transformation.

“To be honest, I rarely got in touch with other Chinese Americans before February this year because I don’t live in a Chinese-American neighbourhood,” said Su, who moved to the United States in 2008. In stark contrast to the role it plays in mainland China, WeChat has become an unlikely champion of democracy on the US presidential campaign trail by giving a voice to the Chinese Americans who have long been silent on American politics.

While political discussions and protest calls may be stifled quickly on the social messaging app in mainland China, Chinese Americans across the US are using it to rally support for their favoured candidates. Asian-Americans made up only 2.9 per cent of voters in 2012 but the ethnic group is among the fastest growing in the US, up from 1.7 per cent in 1996.

Online chat groups are amplifying that voice. In June, about 40 members from the Chinese Americans for Trump WeChat group were invited to meet the candidate at a private event. Su said the group had since ballooned to more than 10,000 members and its core organisers, including herself, had been in close contact with senior campaign staff and the Republican Party.

Such groups, she said, represented different parts of the Chinese-American community. Some are based on geographical location such as the state or the city they live in, while others are based on their occupation or social circle.

She said Chinese immigrants who had arrived in the US in the last two decades were at the forefront of the new political wave. Many were well-educated and tended to be more sensitive to changes in American society.

“We Chinese Americans are often put at a disadvantage, partly due to language barriers, and more often because we are not good at expressing ourselves,” Su said. “We are brought up in a culture to be humble … and not to cause trouble.”

Jay Song, president of Washington Chinese Media, who is organising a Chinese community debate on Saturday, said: “We must give credit to WeChat for making political discussions a lot more convenient and thus realising an unprecedented enthusiasm in presidential politics among Chinese Americans.

“Many people may not be interested in politics in the first place, but as long as they have been involved, possibly passively, in the group discussions of those elections-related topics they will have no other choice but to get involved. That’s why we are seeing unusually high activism among Chinese Americans, most of whom rely on WeChat to communicate with their friends even in the US, this year,” he said.

But while online groups were a key vehicle for political participation among Chinese Americans, they were also a platform for resentment and political attacks, said Paul Zhu, a supporter of Democratic candidate Hillary Clinton and managing director of the Pender Professional Centre, a real estate company in Washington.

“Many of the Trump supporters are particularly aggressive and even make personal attacks,”

Zhu said. “Clinton supporters who are active online, including myself, have been attacked with malicious comments.”

He said Trump supporters described Clinton backers as “ignorant” or even called them “idiots”. Their extreme behaviour mirrored the rhetorical style of the candidate himself, he said.

“I think that Trump has brought out the worst side of human nature … Clinton supporters tend to be more rational,” Zhu said.

Such heated political discussions are driving a wedge between Chinese Americans, according to a New York-based university professor who did not want to be named.

He said he hid his support for Trump from his colleagues, who were mostly Clinton backers, because the two camps were increasingly divided and support for Trump could cost him his job.

“I have joined about 20 WeChat groups, some of them are what we call ‘exchange fire groups’ where supporters of both candidates debate,” he said.

The discussions were so heated that some Clinton supporters would “report” Trump supporters to their bosses, he said.

“Revealing one’s political views, especially if you were a Trump supporter, was particularly sensitive for civil servants or employees of big companies because [the senior management of those companies] tended to support the Democrats,” he said.