The Trump and Harris election camps are sparring over whether to mute microphones when the US presidential candidates face off in their debate on September 10.

Kamala Harris’s team wants the microphones to stay on throughout the ABC debate, in contrast to the disastrous Trump-Biden debate when they were muted unless it was the candidate’s turn to speak.

However it seems Donald Trump’s handlers want to keep the same rule as the previous CNN stoush with President Joe Biden. At the time, that was a rule demanded by the Democrats.

Trump himself appeared to go against the Republican campaign’s efforts to keep the microphones quiet when he said on Monday: “It doesn’t matter to me”.

“I’d rather have it probably on, but the agreement was that it would be the same as it was last time,” Trump said.

But he accused the Democrats of changing the rules “because she [Kamala Harris] can’t answer questions”.

“The deal was we keep the same rules”,” he said.

Harris campaign communications director Michael Tyler responded to Trump’s comment by saying “I think this matter is resolved” because Trump “doesn’t care”.

“Unless Donald Trump allows his handlers to overrule him, we’ll have a fulsome debate between the two candidates with live microphones, where both candidates will be able to lay out their vision for where they want to take this country,” he said on MSNBC.

The issue was first reported by Politico. It seems Harris’s side saw the downside of muting Trump’s microphone in the last debate when his comments were not heard by the audience but put Biden off his game.

Earlier, Trump’s team said they had agreed to the same muting rules as the previous debate hosted by CNN.

“Enough with the games. We accepted the ABC debate under the exact same terms as the CNN debate,” Trump campaign senior adviser Jason Miller said.

“The Harris camp, after having already agreed to the CNN rules, asked for a seated debate, with notes, and opening statements. We said no changes to the agreed upon rules.

“Interesting that this is only coming up now that the Harris campaign has started their debate prep.

“Even their own campaign spokesman said the debate about debates was over. Clearly they’re seeing something they don’t like.”

Harris’s senior adviser for communications Brian Fallon told Politico Trump’s people preferred the muted microphone because “they don’t think their candidate can act presidential for 90 minutes on his own”.

“We suspect Trump’s team has not even told their boss about this dispute because it would be too embarrassing to admit they don’t think he can handle himself against Vice-President Harris without the benefit of a mute button.”

Looming showdown

Harris has two weeks to prepare for what could be her only presidential debate against Trump, a September 10 showdown that could dramatically shift the direction of the US presidential election race.

The first debate, of course, effectively forced Biden to drop out of the race.

Harris has yet to sit down for even one comprehensive media interview to face difficult questions about her flip-flops on policy in recent years, her leadership style and the focus on race and gender that looms over her historic candidacy.

“We can’t put our heads in the sand. She’s a black woman. The bar is going to be higher for everything,” said John Anzalone, a pollster who has served the past three Democratic presidential nominees.

“Guess what? That means, even mistakes. Mistakes are going to be magnified.”

At the same time, Harris’s allies acknowledge she remains largely undefined in the minds of many voters, having operated in Biden’s shadow for much of the past four years. The relative anonymity offers both opportunity and risk.

“The bad thing about vice-presidents is that nobody knows who you are. The good thing about vice-presidents is nobody knows who you are,” said David Axelrod, who was chief strategist for former Democratic president Barack Obama.

For now, Harris’ team feels no urgency to roll out a comprehensive policy platform or sit for media interviews that might jeopardise the positive vibes that have defined her nascent campaign and produced a flood of campaign donations and a growing army of swing-state volunteers.

During meetings throughout the week of the Democratic National Convention, Harris’s advisers cast her policy agenda as a continuation and expansion on Biden’s first-term achievements, particularly on economic matters, even if it may look and sound different in some cases.

Harris has notably dropped her opposition to fracking and her support for Medicare for All, which were defining features of her 2019 presidential campaign. Her aides insist her values remain the same, but she’s embraced more centrist policies out of pragmatism.

Meanwhile, Harris’s allies believe it’s only a matter of time before Trump settles on an effective line of attack.

In recent days, he has adopted a kitchen-sink approach against Harris that includes attacks about her racial identity, her laugh, her record as Vice-President and her history as a “San Francisco liberal”.

“He’ll figure out how to get a message and land a political punch,” Pennsylvania Governor Josh Shapiro, who delivered a prime-time convention speech this week, said of Trump.

Polling reveals that voters’ views of Harris have shifted relatively rapidly in the month since Biden stepped aside and she became the de facto nominee.

In a June AP-NORC poll, just 39 per cent of Americans said they had a favourable opinion of Harris and 12 per cent said they did not know enough to say.

After Biden stepped aside, an August AP-NORC poll found that 48 per cent of Americans had a favourable opinion of Harris with just 6 per cent saying they did not know enough to have an opinion. The latest poll also showed that 27 per cent of adults have a “very” favourable opinion of Harris, up from 14 per cent in June.

The sharp shift raises the possibility that public opinion could change again as voters learn more.

It also raises the possibility that Harris’s momentum has less to do with her candidacy than a sense of relief among Democrats that Biden stepped aside.

-with AAP