With the Senate campaign of Maine’s Graham Platner blowing up in their faces, Democrats everywhere are giving each other tearful gobs of solace and advice. Some are comparing Platner’s scandal-driven collapse and last-minute withdrawal to the 2024 presidential campaign, when a befuddled Joe Biden withdrew in early July and his vice president, Kamala Harris, was handed the nomination. The comparison reflects deep pessimism among Dems about their chances now of winning the Maine seat held by GOP incumbent Susan Collins, which is crucial to their hopes of gaining a Senate majority. Part of that pessimism stems from the fact that...