The Atlantic article said Trump had shown disdain toward American soldiers who had died in service and confusion as to why they would sacrifice themselves for their country. The White House has repeatedly denied the account, but that hasn't stop Biden from expressing his outrage at the alleged remarks.

Trump has also repeatedly expressed his dislike for John McCain, going so far in 2015 as to say the former Vietnam prisoner of war was "no hero" and "I like people who weren’t captured." More recently, he's repeated that he was never a fan of the Arizona senator and 2008 Republican presidential nominee who died Aug. 25, 2018.

McCain and Biden shared two decades in the Senate together. Cindy McCain spoke about their friendship in a tribute during the Democratic National Convention, where she also touted Biden's ability to work across the aisle and prioritize national security.

Over 100 former McCain staffers also joined a chorus of Republican staffers in endorsing Biden last month, despite having worked to beat him when he was the vice presidential nominee in 2008.

"Given the incumbent president’s lack of competent leadership, his efforts to aggravate rather than bridge divisions among Americans, and his failure to uphold American values, we believe the election of former Vice President Biden is clearly in the national interest," they wrote in their endorsement.