“There are two questions we will never have to ask ourselves, ‘Who is this man?’ and ‘Can we trust this man with the presidency?’ ” — Fred Thompson on John McCain, September 2 This was the most effective line of the entire Republican convention: a ringing affirmation of John McCain’s authenticity and a not-so-subtle indictment of Barack Obama’s insubstantiality. What’s left of this line of argument, however, after John McCain picks Sarah Palin for vice president? Palin is an admirable and formidable woman. She has energized the Republican base and single-handedly unified the Republican convention behind McCain. She performed spectacularly...