Vice President Kamala Harris has full confidence that President Biden has the stamina and around-the-clock clarity of mind to handle the domestic and international crises in front of him, a Harris spokesperson tells Axios.

Why it matters: The June debate that led Biden to drop his re-election campaign raised questions about Biden's mental fitness — and whether Harris had any concerns beforehand.

Driving the news: Axios asked Harris' campaign Saturday whether she could "fully assure" voters that there is nothing to be concerned about Biden's "hour-by-hour performance."

• Harris spokesperson Ian Sams quickly responded: "Of course."