He asked Kirby — who joined White House Press Secretary Karine Jean-Pierre to assist with the Russia prisoner-swap insight— if the US considered the possibility that "the Saudi government may have deliberately exposed the President to the coronavirus."
Stunned, Nelson said that the question was out of his "scope" and that he should refer to Jean-Pierre to answer the question about Biden's medical condition.
He also noted that he was unaware of where the idea came from and what caused Nelson to frame the question that way.
"The idea that a foreign nation-state would — would deliberately try to infect the President of the United States with a virus is just ludicrous — just absolutely ludicrous," Kirby said.
He added: "There's nothing to it. And it should be treated as the — as the ridiculous idea that — that it is."
This isn't the only time Nelson has perplexed officials in press briefings.