"Chris Dempsey, founder of Delegates are Democracy, a grassroots organisation working with delegates, said: "If the president withdraws, from a rules perspective it is wide open and delegates can vote for whoever they want. From a political perspective, if he were to endorse his VP, the delegates may follow but nobody is required to do so."
Read the full article here: https://www.ft.com/content/1fa1a199-a52d-4a97-8b01-9158a8526c9e