The most dramatic instance of that is Biden’s continued insistence on lying about the circumstances surrounding the horrifying deaths of his wife and daughter in a terrible car accident. It is not the case, as Biden has said on many occasions, that they were killed by a drunk driver, an irresponsible trucker who “drank his lunch,” as Biden put it. That is a pure fabrication, and a slander on the man who was behind the wheel of that truck and who was haunted by the episode until the end of his days. Imagine yourself in the position of that man’s family, whose natural sympathy for Biden’s loss must be complicated by outrage at his persistent lying about the relevant events.

Why would Biden lie about the death of his wife and daughter? Why would he lie about the already-heroic efforts of American soldiers? In both cases, to make the story more dramatic, to give himself a bigger and more impressive narrative arc. That he would subordinate other people — real people, living and dead — to his own political ambition in such a callous and demeaning way counsels strongly against entrusting him with any more political power than that which he already has wielded.

Biden lies about matters great and small. He lies about his trip to Afghanistan. He lies about the death of his wife and daughter. He is wildly dishonest about his role in the Iraq War and the 1994 crime bill, landmark moments in his legislative career that later became political liabilities. And whatever the state of his brain today, he was not senile back in 1987, when he plagiarized the words of Margaret Thatcher and Neil Kinnock for his own speeches. Like his lies, his plagiarism is part of a lifelong habit: As recently as this year, he was filling out his policy papers with uncredited — stolen — material from advocacy groups.