 But when asked about a Parkinson's expert that was at the White House several times in the last year, she would not say if it was for President Biden. Jean-Pierre said it was a security issue and she would not respond. Joe Biden says he's staying in the presidential race in a defiant letter to Democrats on Capitol Hill, rejecting calls for him to step aside. First Lady Jill Biden, speaking at a campaign event in Wilmington, North Carolina, says she backs her husband's decision. For