The presidential campaigns of Kamala Harris and Donald Trump have locked horns over muted mics during the September debate
The presidential campaigns of Kamala Harris and Donald Trump have locked horns over muted mics during the September debate AFP

A much-anticipated US presidential debate next month between Kamala Harris and Donald Trump was thrown into question Monday over the subject of muted mics, as the Republican threatened to pull out.

Trump had already balked at debating in the September 10 showdown, which comes on the heels of Harris's rapid rise as the Democratic Party's nominee following President Joe Biden stepping down.

On his Truth Social media platform Sunday, Trump accused TV broadcaster ABC of bias, posting: "I ask, why would I do the Debate against Kamala Harris on that network?"

The Trump and Harris campaigns were also locked in disagreement Monday over whether each candidate's microphone would be muted when the other spoke.

Harris's campaign alleged that Trump's camp was vying to keep the mics off to protect him from any off-color comments or if he loses his temper during the debate.

"We believe both candidates' mics should be live throughout the full broadcast," Harris communication director Brian Fallon said in a statement.

He alleged that "Trump's handlers prefer the muted microphone because they don't think their candidate can act presidential for 90 minutes."

During a June 27 debate on CNN between Trump and Biden, who was the Democratic candidate at that time, microphones were turned off when it was not a candidate's turn to speak.

It was a condition negotiated by Biden, and one that was meant to apply to the September debate on ABC as well.

But Harris, who replaced Biden after his disastrous performance at the CNN debate, is pushing for a return to the norm of keeping microphones on.

The Trump camp maintains that the debate should occur under the already agreed conditions.

Trump himself further muddied the waters on Monday when referring to his mic, saying "I don't know, doesn't matter to me. I'd rather have it probably on," according to video broadcast by NBC.

"The agreement was that it would be the same as it was last time. In that case, it was muted," he said.

He also attacked Harris, calling her "not a smart person" and alleging that "she doesn't want to debate."

Biden's calamitous performance in the last debate on top of slippage in the polls sounded the death knell for his campaign.

Harris, who is slightly ahead of Trump in polling, is hoping to maintain her momentum or even widen the gap.