A former defense secretary who served under presidents from both parties says that when it comes to national security, he believes Donald Trump "is beyond repair."
Robert Gates writes in Saturday's Wall Street Journal that the Republican presidential nominee is "stubbornly uninformed about the world and how to lead our country and government, and temperamentally unsuited to lead our men and women in uniform."
Gates concludes: "He is unqualified and unfit to be commander-in-chief."
Trump has posted a response on his Twitter account saying he's never met Gates, and Gates "knows nothing about me."
Trump then says of Gates: "Look at the results under his guidance -- a total disaster!" Gates was Pentagon chief under presidents George W. Bush and Barack Obama.