Over the past year the United States and, secondarily, the rest of the world, have been bombarded with the Democratic Party’s take on “Russia collusion.” Democrats have persistently declared that President Donald J. Tramp’s political ascendancy signals Armageddon. The insults started with the snarky “he’s not one of us,” to myriad accusations of anti-Semitism, racism, serial sexual harassment, xenophobia, vulgar speech, facilitation of white supremacists and violence, a crashed economy, and soured foreign relations. When none of these accusations stuck, they settled on an unrelenting, unsubstantiated drumbeat of claims that the Trump campaign colluded with Russia to affect the outcome...