In a torch-passing speech, President Joe Biden vowed that he would be “the best volunteer” to help the campaign of his vice president, Kamala Harris. Biden also touted his accomplishments and took shots at the Republican presidential nominee, Donald Trump. Several claims by Biden, and some from other Democrats at the Chicago convention, missed the mark. Biden misleadingly cited “historic joblessness” in talking about his Inauguration Day in 2021. The economy was still struggling then, but...