The upcoming U.S. presidential debate has become a battleground, with Donald Trump and Kamala Harris's teams at odds over the use of open microphones. Trump has threatened to withdraw from the event, accusing the ABC network of bias, according to a Reuters report.

What Happened: Trump, in his third presidential run, hinted at his non-participation in the ABC network-hosted debate via a social media post on Sunday. He questioned the network's impartiality, writing, "Why would I do the Debate against Kamala Harris on that network?"

On Monday, Harris' spokesperson, Brian Fallon, expressed the vice president's campaign's desire for the candidates' microphones to remain on throughout the event. This contrasts with the previous presidential debate where mics were muted when the other candidate was speaking. Fallon urged Trump to "stop hiding behind the mute button."

In response, Trump's campaign senior adviser, Jason Miller, stated that they had agreed to the same terms as CNN's June debate, which included muted microphones. He rejected any changes to the agreed-upon rules. However, Trump later expressed his preference for his microphone to be kept on, showing his distaste for the mute option used in the last debate.

"I'm not spending a lot of time on it. I think my whole life I've been preparing for a debate," Trump said, according to the report.

"You can't cram knowledge into your head, for you know, 30 years of knowledge in one week. So, you know, there's a little debate prep, but I've always done it more or less the same way."

The ABC network has not yet commented on these developments. The debate, agreed upon by Biden and Trump, is scheduled for September 10.

Why It Matters: The September 10 debate between Vice President Harris and Republican candidate Trump is seen as a critical event. However, Trump's recent social media post has cast doubt on his participation, citing perceived bias from the ABC network, owned by Walt Disney Company.

A recent Rasmussen poll, which may be an outlier, showed Trump leading Harris by 3 points, though Harris has led in most polls. The poll was conducted before significant political events, including the Democratic National Convention and Robert Kennedy Jr.'s campaign suspension.

Meanwhile, Harris held a slight edge in betting odds, but the race remained close, with Trump slightly ahead in some prediction markets. Harris had also shown leads in key swing state polls.