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

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

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

Republicans have regularly criticised Ms Harris, 59, during Mr Biden’s term in office, but the attacks this week represented a sharp and seemingly coordinated escalation that appeared to be linked to increased talk about her possibly replacing Mr Biden as the Democratic presidential candidate.

The National Republican Congressional Committee, which oversees House Republican races, called her Mr Biden’s “enabler in chief”.

MAGA Inc., a fundraising super PAC supporting Mr Trump, meanwhile, released a statement calling her the “invasion czar”. In March 2021, Mr Biden said Ms Harris would lead efforts with Mexico and Central American nations to address illegal immigration.

US border

Republicans have since seized on that to accuse her of failing to stem the flow of millions of migrants crossing illegally into the United States, although she was never directly responsible for securing the southern border.

“Kamala Harris is incompetent. She’s proven to be the weakest, worst vice president in history, and she has 100 per cent supported Joe Biden in every single disastrous policy that he has implemented over the last four years,” said Karoline Leavitt, a spokesperson for the Trump campaign.

The Biden campaign pushed back against the escalating Republican criticism without addressing the question of whether the vice president is waiting in the wings.

“Vice President Harris is proud to be President Biden’s running mate,” said Rhyan Lake, a campaign spokesperson for Ms Harris. “No matter what false attacks Trump and his extreme allies make, she will continue to defend the Biden-Harris record and prosecute the case against Donald Trump.”

The swipes at Ms Harris by Mr Trump’s camp were reminiscent of a similar tactic that the Republican Trump, president from 2017-2021, used to successfully undermine Ron DeSantis, his main Republican rival, before the Florida governor jumped into their party’s 2024 election primary race last year.

Corey Lewandowski, a longtime Trump adviser, told Reuters Ms Harris was politically vulnerable given her role in addressing illegal immigration, among other issues that are part of extensive research the party has gathered on her record.

Trump’s unusual silence

A former senior staffer in the Trump White House who is still in contact with the Trump campaign said the newfound emphasis on Ms Harris made sense.

“If Joe Biden stays on top of the ticket, given what we’ve seen, she takes on even more importance. But if he does step aside, she’s the potential candidate. This is about defining her,” the staffer said, pointing to her low approval ratings in public opinion polls.

Despite her consistently low approval ratings, a Reuters/Ipsos poll earlier this week showed Ms Harris to be as formidable an opponent to Mr Trump as Mr Biden. In a hypothetical match-up, Mr Trump led Ms Harris by a single percentage point, 43 per cent to 42 per cent.

The clamor by Mr Trump’s allies is in stark contrast with the unusual silence from the normally voluble former president. Since Mr Biden’s poor debate performance, Mr Trump has laid low, making few public appearances or public statements.

“This shows a maturation of the candidate himself. You can teach an old dog new tricks. He’s showing increased discipline and message control,” said a senior adviser to the Trump campaign familiar with internal discussions.

Attack ads

Even before the June 27th debate, the Trump campaign was beginning to turn its attention to Ms Harris, releasing an attack ad online that mocked her for repeating lines in her speeches.

An online meme promoted by Republicans showed Ms Harris repeating the same phrase “unburdened by what has been” again and again in remarks.

Ms Harris’ defenders say she has become more of a target because of her leading role in attacking Mr Trump over abortion rights and her vigorous defence of Biden on the campaign trail.

If Mr Biden were to exit the race before the Democratic National Convention in August, there is no guarantee Ms Harris would be the nominee. But as vice president, she likely would be first in line. She would benefit from Mr Biden’s immense campaign war chest and likely see a large segment of Democrats rally around her in a bid to avoid a bitter intra-party battle.

And as the first Black vice president in US history, she provides a bridge to the party’s most dependable voting bloc. Her background and relative youth would make for a sharp contrast with Mr Trump, 78.