It is not often that you see Democrats tear up over a message from former vice president Dick Cheney. However, his campaign ad for his eldest daughter, Rep. Liz Cheney (R-Wyo.) — part swan song, part defiance, part nostalgia — tells us more about the decrepit state of the GOP than any Democrat’s ad has this cycle. “In our nation’s 246-year history, there has never been an individual who is a greater threat to our republic than Donald Trump,” he declares. Coming from a former vice president and defense secretary responsible for defending America against hostile nations and foreign terrorists,...