President Donald Trump has he won't "waste his time" on a virtual presidential debate on 15 October and will hold a rally instead.
Joe Biden has said he would participate, but has suggested moving it to 22 October to prevent the president from "evading accountability".
The proposal for a video debate had been aimed at protecting the health and safety of all involved, as Trump has tested positive for the coronavirus.
Trump told Fox News that the plan was unacceptable.
Washington correspondent Simon Marks speaks to Susie Ferguson.