51 is an interesting number, isn’t it? It’s one shy of a deck of cards. It’s the mysterious “Area” where a top-secret U.S. military installation associated with UFOs is located. It’s exactly three times the number of intelligence agencies who confirmed Russia tried to interfere in the 2016 election. It’s a large number — an impressive one, even. And when 51 current and former intelligence officials sign and publicize a letter, it’s designed to get your attention and, undoubtedly, persuade you of the import of what is being said. And so it did — for many Americans, the characterization of...