President Donald Trump was defiant in the face of an impeachment probe as he sought to convert the threat to his presidency into a political asset on the campaign trail yesterday, with biting attacks on potential Democratic challenger Joe Biden.

Facing an investigation provoked by his unprecedented call for Ukraine and then China to assist in digging up dirt on his political rivals, Trump continued to lay into Biden and his son Hunter, whom he has accused without evidence of trading on the vice-presidency for financial gain.

"The Bidens got rich, and that is substantiated, while America got robbed," Trump said.

The rally in Minneapolis was the first since Democrats began proceedings two weeks ago to remove him from office. It served as a proving ground for the President as he tries to use the impeachment inquiry to energise supporters for his 2020 campaign by casting himself — and his supporters — as victims of Democrats in the Washington swamp.

Advertisement

"They want to erase your vote like it never existed," Trump said. "They want to erase your voice and they want to erase your future." The rally, scheduled before House Speaker Nancy Pelosi announced the impeachment investigation, came at a pivotal moment for Trump. His campaign strategy is focused on motivating his core supporters, rather than trying to win over a diminishing number of undecided voters, and the resonance of his appeal to the faithful may determine his second-term chances.

The rally at Target Centre, the city's basketball arena, drew thousands of supporters as well as protesters outside.

Meanwhile, Ukraine's President yesterday insisted that he faced "no blackmail" from Trump in their phone call that led to the impeachment inquiry, distancing himself from the US political drama and trying to claw back his own credibility.

Volodymyr Zelenskiy said for the first time that his country will "happily" investigate the conspiracy theory pushed by Trump that it was Ukrainians, not Russians, who interfered in the 2016 US presidential election. And he encouraged US and Ukrainian prosecutors to discuss investigating a gas company linked to Joe Biden's son Hunter, although no one has produced evidence of criminal wrongdoing by the former US Vice-President or his son.

"There was no blackmail," he said. "We are not servants. We are an independent country."

- AP