Donald Trump supporters can disparage many of the meritless, petty attacks on their candidate, from the so-called "Star of David scandal" to the holes-in-Melania-Trump's-immigration story. I don't blame them. I disparage them, too. But I must tell you this: If Trump secretly conducted business in communist Cuba while Fidel Castro was its president, the Republican presidential nominee should be prosecuted to the fullest extent of the law, not elected to the highest office in the land.