Paul Selva, once one of Trump's top generals, endorses Biden

FILE PHOTO: Vice Chairman of the Joint Chiefs of Staff U.S. Air Force General Paul Selva speaks at the Center for Strategic and International Studies in Washington, U.S., October 28, 2016. REUTERS/Gary Cameron

(Reuters) - Once one of President Donald Trump's most senior military advisers, retired General Paul Selva is joining a large group of former Pentagon leaders to publicly endorse Democratic candidate Joe Biden for the Nov. 3 presidential election, according to a letter seen by Reuters.

Selva, who served as vice chairman of the Joint Chiefs of Staff until July 2019, appears on a list of 489 national security experts - including former military leaders, ambassadors and White House officials - who signed a letter being released on Thursday that declares Trump "not equal to the enormous responsibilities of his office."