In her latest column, which appeared in Saturday's publication, Sullivan attacked the president and accused him of using the briefings as a "substitute" for his campaign to push his own agenda.
"More and more each day, President Trump is using his daily briefings as a substitute for the campaign rallies that have been forced into extinction by the spread of the novel coronavirus," Sullivan wrote. "These White House sessions — ostensibly meant to give the public critical and truthful information about this frightening crisis — are in fact working against that end."