Donald Trump's campaign and some of his allies have launched a pre-emptive political strike on Vice President Kamala Harris, moving swiftly to try to discredit her amid talk among some of her fellow Democrats that she might replace U.S. President Joe Biden atop the party's 2024 presidential ticket.

On social media and in a flurry of statements over the past 48 hours, Trump's campaign and his Republican allies appear to be laying the groundwork for an all-out assault on Harris should the 81-year-old Biden decide to end his re-election bid following his feeble debate performance last week.

While Biden has insisted he is not quitting the race four months before the Nov. 5 election, and Harris has stood firmly behind him, the Trump campaign has little to lose by attacking the vice president now, so that if Harris does emerge as the nominee, she might do so in a weakened state.